Doc 0000173971

The image displays a digital banner with a stylized title "THE BLACK VAULT" in white, outlined lettering with a blue glow effect. To the left, a graphic represents a stylized, circular vault door with intricate mechanical details and a blue light source emanating from what appears to be the right side. The right side of the banner contains white text on a black background, explaining that the document originates from "The Black Vault," an online repository of declassified government documents. It specifies that the record is from the "MKULTRA/Mind Control Collection" and provides a URL for downloading the entire collection. I . . INVESTIGATION OF ELECTRIC FISHES FINAL REPORT - PHASES 1 AND 2 by Prepared under Contract . \ August 1974 - SUMl'MRY Electric fishes have one or more transmitting electric organs and an array of electroreceptors. The system is controlled by special nuclei lo cated in the brain. The elements of the electric transmitting organs, called electroplates, are described; and the electromotive force (EMF) generated by each electroplate and of the entire organ is discussed. The waveform of the signals was studied and the structure of the electric organs investigated. The biochemistry of the chemotransmitter and the metabolism of the electro genic tissue is discussed. The physiology of the electric transmitting organs was studied, and their common properties described. Analogy has been made between the electrogenic properties of muscular tissue and the electric organs of fishes. The transversal and lateral resistance of the electric tissue of · the electric eel and torpedo is mentioned. Electroreceptors are special sensors of the lateral line system. Some fishes possess electroreceptors and no electric transmitting organ. The dif ferent kind of electroreceptors are mentioned. The physiology of some of. the electroreceptors of Sternarchus albifrons, a South-American fresh water weakly electric fish were investigated. The electroreceptors of the mormyrid Gnathonemus petersii were mapped and counted. Tonic and phasic electroreceptors were studied. The nervous control and function of the electroreceptors is discussed and the functional character istics of six different kinc:Is of lateral line organs have been considered. The location of objects by the e lectroreceptor system of electric fish is discussed and communication between electric fishes mentioned. i The electric field pattern around the electric fish SternarchtlS albifrons has been plotted and compared with the theoretical pattern of a dipole. The perturbing effects of various confinement cages on the electromagnetic field pattern were Distortions of the wave form with distance were d~termined. recorded. The maximum detection range of the electric fishes GnathonemtlS sp. and Gymnotus carapo to stainless steel, iron, brass and nylon is presented. At the critical separation between the fish and sample, (assumed to be the threshold detection distance) the fish increased the rate of its signals or ceased transmission entirely. The effects of sample material, sizes, form and azimuth on the threshold detection distance are presented. Behavioral experiments have bee.n formed using Gymnarchus niloticus to determine the threshold of detection distances. These experiments were also performed in the fiberglass tank The page appears to be the cover page of a report. It features a large rectangular box containing the title "INVESTIGATION OF ELECTRIC FISHES". Below this, centered text reads "FINAL REPORT - PHASES 1 AND 2". Further down, the word "by" is present, followed by "Prepared under Contract". The date "August 1974" is at the bottom right. A circled number "261" is visible in the bottom right corner. There are no photographs, diagrams, forms, stamps, or redactions. increased the rate of its signals or ceased transmission entirely. The effects of sample material, sizes, form and azimuth on the threshold detection distance are presented. Behavioral experiments have bee.n formed using Gymnarchus niloticus to determine the threshold of detection distances. These experiments were also performed in the fiberglass tank with and without an aluminum foil liner. Photos and movie films were made to record the fishes beha\ior. Gnathonemus sp. is a fresh water, low rate, high frequency pulse weak electric African mormyrid fish. Gymnotus carapo is a fresh water, medium rate, medium frequency pulse, weak electric South-American gyrnnotid fish. Despite their physiological and electric differences, both these fishes stopped transmitting electric signals if the object was of high conductance and was brought close to the fish(< 50 em). Because the fishes were very excited and tried to escape even after they had ceased transmitting, it seems reasonable to assume that they continue to detect the objects in the water using their sensors in a passive mode. The electroreceptors of Gnathonemus sp. were mapped to location and morphological type and related to the area. We recorded the response of some electroreceptors of Gnathonemus sp. The presence of one type of receptor in the sensor matrix which is sensitive to mechanical movement was established. ii A qualitative assessment of the fishes ability to navigate within a difficult maze of nylon fishing line has been made. Blind electric fishes (Gymnarchus niloticus, Sternarchus albifrons, and Gymnotus carapo) easily navigate through such mazes. Photos and movie film were made. These behavior experiments were performed in a 12 foot diameter fiberglass tank and under two separate electric boundary conditions. The threshold sensitivity for detection of a magnetic field is pre sented in graphic form for: Gymnarchus niloticu5, Sternarchus albifrons and Gnathonemus sp. Photos were made and the behavior of the fishes has been filmed. The threshold detection limits of Gymnarchus niloticus and Gnathonemus sp. was determined for a D. C. electric field Wlder two different electrical boundary conditions. The reactions of Gymnarchus niloticus, Gnathonemus sp. and Sternarchus albifrons, to recordings of their own electrical signals and to those of other individuals of the same species are presented under two very different electrical backgrounds. Photos and movie films were taken. We arrived at the conclusion that our knowledge of electroreceptors arrays and lateral line sensory receptors of electric fishes is incomplete~ In vestigation in their function and to those of other individuals of the same species are presented under two very different electrical backgrounds. Photos and movie films were taken. We arrived at the conclusion that our knowledge of electroreceptors arrays and lateral line sensory receptors of electric fishes is incomplete~ In vestigation in their function and biochemical composition would put us in the position of designing systems having similar properties with electric fishes for underwater detection, location and identification of objects. The importance of neurotransmitters is stressed and the role of electric fishes in the study of these complex energetic systems is mentioned. Electric fishes offer some unique properties in the study of electrophysiology and neurochemistry. iii CONTENTS . . . . . . . . . . . . . . . . . . . . . . ....... . 1. INTRODUCTION 1 2. TECHNICAL DISCUSSION .••••••.••••.••••••••••• 6 2. 1 THE TRANS:MITTING ELECTRIC ORGANS OF ELECTRIC FISHES • • • • • • • • • • • • . • • • • • • • • • • . 6 2. 1.1 The Electromotive Force of Electric Organs • • 6 2. 1. 2 The Waveform of Electric Signals • • • • • • • • • 6 2. 1. 3 The Structure of the Electric Organs. • • • • • • • 12 2. 1. 4 Chemical Composition of the Chemotransmitter and the Metabolism of the Electrogenic Tissue • 12 2. 1. 5 Physiology of the Electric Organ • • • • • • . • • • 22 2. 2 ELECTRORECEPTORS AND ELECTRORECEPTION • • 30 2. 2. 1 Distribution of the Electrosensory Receptors • • 32 2. 2. 2 Tonic and Phasic Electroreceptors • • • • • • • • • 36 2. 2. 3 The Control and Function of the Electro- receptors ... -. . . . . . . . . . . . . . . . . . . . . . . 44 2. 2. 4 Active Electroreception • • • • • • • • . • • • • • • . 49 2. 2. 5 Passive Electroreception • • • • . • • . • • • • • • • 51 2. 2. 6 Coding of the Electrical Signal of Electric Fishes . • • • . . • . • . • . • The document is a declassified CIA report concerning electric fish and their electroreceptors. The page contains a "SUMMARY" section with no visual elements beyond standard text. There are no photographs, handwritten annotations, official stamps, forms, diagrams, tables, redactions or visual evidence of experimental procedures. The document appears to be purely textual, with the exception of a small letter "i" at the bottom of the page, which may indicate a page number. The document is a single page of a typed report with no images, stamps, or handwritten annotations. The text discusses electric fish and their sensory capabilities, specifically focusing on the electric field patterns and detection ranges of various species like *Sternarchus albifrons*, *Gnathonemus sp.*, and *Gymnotus carapo*. The page contains no visual aids like diagrams or photographs, and there are no redactions. The only non-textual element is a lowercase Roman numeral "ii" at the bottom, likely indicating a page number. • • • . 49 2. 2. 5 Passive Electroreception • • • • . • • . • • • • • • • 51 2. 2. 6 Coding of the Electrical Signal of Electric Fishes . • • • . . • . • . • . • • • . • • • • • . • • . • • • 52 2. 3 EXPERIMENTAL FINDlliGS • • • • • • .. • • • • • • • • • • • 53 2. 3. 1 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 2. 3. 2 The Electromagnetic Field Generated by Sternarchus albifrons a South American Fresh Water Weakly Electric Fish • • • • • • • • • • • • • 57 iv - CONTENTS (Cont'd.) 2. 4 BEHAVIOR EXPERIMENTS FILMED ON STANDARD 8 FILM .......•......... ~ . . . . . . . . • • . . . . 77 2. 4. 1 Experiments Needed to Assess Sensitivity, Range and Effectiveness of the Electric Fishes to Detect Objects and Communicate Under- \Va,ter • • • • • • • • . . • • • • . • • • • • • • • • • • • • 77 2. 5 BEHAVIORAL EXPERIMENTS USING PHYSIOLOGICAL METHODS ....•.......................•.· 94 3. CONCLUSIONS AND RECO:M1\1ENDATIONS •••••••••••• 96 REFERENCES ................. ·. . . . . . . . . . . . . . 99 v 1. lliTRODUCTION In this final report we would like to mention and summarize the morphological, physiological and behavioral aspects of some electric fishes. 1 2 Darwin( ) and Dahlgreen( ) consider the electric organs of fishes as a dif ficult case to be e:h.1)1ained by what evolutionary steps they may have been produced. Except the lw1g-snail Daudebardia from Asia Minor which has 3 been reported as electrogenic by Leder and mentioned by Garten, ( ) the . only class in the animal kingdom known to possess specialized electric organs is the class of fishes. The electric transmitting organs are derived in most electric fishes from modified muscular tissue. We observed this fact in Gymnarchus niloticus, an African fresh-water weakly electric fish. But there are exceptions like the American fresh Sou~h v.>ater weakly electric This page is a typed document with no visible photographs, stamps, or handwritten annotations. There are no forms, diagrams, or tables present. The text discusses experiments with electric fishes, including their ability to navigate mazes and detect magnetic fields. The document is page "iii" and appears to be the end of a section, as there is a partial horizontal line at the bottom of the page. known to possess specialized electric organs is the class of fishes. The electric transmitting organs are derived in most electric fishes from modified muscular tissue. We observed this fact in Gymnarchus niloticus, an African fresh-water weakly electric fish. But there are exceptions like the American fresh Sou~h v.>ater weakly electric fish Sternarchus albifrons, whose transmitting electric organ is derived from modified nervous tissue. Mutations by virtue of change enhanced the and fitness of the organism, giving surv~val it a superiority over the other species either in communication, in naviga tion, or food finding and defense against enemies. Because the successive mutations stand the test of natural selection, they produced an organism greatly different from its distant forebears. Communication in its large interpretation encompasses any in formation needed to produce a change in a state. Change from one state into another raises entropy, and energy is needed to raise the state from one level to the other. Compared with the complete electrochemical communication system of the electric fishes, all others used by living organisms are less efficient. By its nature, the nervous system uses electrical impulses as a 1 - communication means. In order to communicate and usc a language, human beings have to transform electrical and chemical energy into mech anical and acoustical energy for transmitting messages and to transform optical, acoustical, or mechanical energy into electrical and chemical energy for receiving messages. Always energy is lost and entropy is raised. fishes are the only ones which use only electrochemical El~ctric energy for communication purposes with minimum loss in energy and mini mum rise in entropy. Fishes can communicate reliably underwater, but we have difficulties in doing this although we dispose of energies many orders of magnitude larger than those used by fishes. For this reason and for their ability to use their electrosensory system for detection, identification and location of underwater objects it seemed appropriate to study some of the electric fishes, their transmitting · organs and their electroreceptors. An investigation has been conducted for the .~for a period of three years which resulted in a final report. . / Beh.a:vioral and physiological experiments have been conducted by the author on the Electrophoridae, Sternarchidae, Gymnotidae, I l\1ormyridae, Gymnarchidae, and Malapteruridae. Other in vestigators have studied the physiology, the morphology and behavior of a few species of electric fishes, but the subject is far from being completely understood. The author This page appears to be the table of contents for a technical document. It is entirely text-based, with no images, handwritten annotations, stamps, forms, diagrams, or tables. There are no visual indications of experimental procedures, equipment, or facilities. The content is organized into numbered sections and subsections with corresponding page numbers. The only non-textual element is the page number "iv" at the bottom center. / Beh.a:vioral and physiological experiments have been conducted by the author on the Electrophoridae, Sternarchidae, Gymnotidae, I l\1ormyridae, Gymnarchidae, and Malapteruridae. Other in vestigators have studied the physiology, the morphology and behavior of a few species of electric fishes, but the subject is far from being completely understood. The author studied also the morphology and physiology of electric fishes in connection with the detection and location of objects and under\t;"ater co_mmunication. For the investigation mostly Sternarchidae were used, but some limited findings in 1\lormirydae and Gymnarchidae have . ) also been studied. We found 'that the electric fishes could use their electric organs (transmitting and receiving) for navigation and commwlication- in other words, pattern recognition. 2 The electric signal recordings and histological evidence indicate that Sternarchus albifrotts has three kinds of clcctroreccptors: ampullary tonic nonsynchronous w1its, ampulbry tonic synchronous units, and tuberous phasic I nonsynchronous tmits. 1 Both are represented by a generator connected to Ii.he resistances and capacitances in series and in parallel. difference between tonic and ph.1 . .sic electroreceptors is that the former have one resistance in series with the generator whereas the phasic elcctroreceptors have a cap acitance. The tonic electroreceptors seem to predominate at a ratio of ap- i proximately five-to-one, compared to the phasic electroreceptors. The I electroreceptors seem to act, to a certain extent, independently of the main electric transmitting organ; at least two of the three types of electroreceptors are asynchronous. Szabo(S) found that the complete denervation of the trans mitting electric organ does not stop the activity of the asynchronous electro receptors (both phasic and tonic). The fish is still capable of responding to conductive and nonconductive objects placed near the fish's body. Denervation of the transmitting organ will affect the capability of certain movement or im pair, to a certain eAi:ent the ability to recognize patter~ Some of the syn chronous tonic units are connected to the same nerve trunk as the acousti colateralis system and connected to-specialized big nuclei in the brain. The most striking fact about fresh water weak electric fish, besides their spontaneous electric organ, is that all of them are provided with a highly developed lateralis line system. Related to this acoustico-lateralis system is an enlargement of the cerebellum, especially in Gymnarchus ~ . niloticus and in lVIormyridae. ~1e unusual importance of the lateralis system in these fish, compared with other teleosts, is not due to This page displays a table of contents from a document, listing chapter and section titles with corresponding page numbers. There is no visual content such as photographs, diagrams, or stamps. The text itself indicates that the document continues from a previous page ("CONTENTS (Cont'd.)"). The items listed suggest a scientific or research-oriented document, with sections on "BEHAVIOR EXPERIMENTS" and "CONCLUSIONS AND RECOMMENDATIONS." The page is otherwise blank apart from the typed text. all of them are provided with a highly developed lateralis line system. Related to this acoustico-lateralis system is an enlargement of the cerebellum, especially in Gymnarchus ~ . niloticus and in lVIormyridae. ~1e unusual importance of the lateralis system in these fish, compared with other teleosts, is not due to an increased nutnber of "ordinary" lateral line sensory organs, but rather to the existence of a great number of specialized sensory organs within this same syste~. .. 3 l This is supporting our hypothesis about a hybrid complex tmderwater pa.ttern recognition system used by electric fishes in recognition of prey, ( pr~- clators, and navigation in general. It is recommended that the other lateralis line systems from different fresh water weak c lectric fishes should be studied ( with the aim to find out the role of the different sensory organs in pattern re- __ i cognition. Finer subdivisions exist between the one and the same type of electro 4 recepto~, but this has not been as yet investigated in a detailed way. ( 0} Knowledge of the physiology and biochemistry of the electroreceptors are incomplete. These studies will provide a basis for Wlderstanding the work ing of the system. Microelectrode recordings from the electroreceptors proper and from their nerve fibers are needed to provide information concern ing the function of the receiving system. By combining the anatomical and functional data of these fishes it could be possible to simulate an equivalent undenr.rater sensory system. Two double feedback mechanisms are envisaged: (1) a system transmitting· a constant frequency electric field and using a phase-synchronous electro receptor responding to either discontinuities in the electric field or to changes in the phase relationship between-the transmitting and receptors; and (2) a second one represented by a variable frequency transmitter and receptor with a change of frequency. An independent dual autorhythmic receptor system could be designed and: (a) increasing or decreasing the autorhythmic ) frequency depending on the direction of movement of the disturbance in the electric field; and (b) responding with a change in the latency depending on / the magnitude of the disturbance, also distinguishing between conductive and nonconductive objects. 4 -- ...~ -------·--'-- ___________ ..,... __ ,_ .,. ...... ------~-- ..... ---·· ..... -.-....... ---- ... _______ ... ----~~----·-- ·--····-.. In any case the key to the object detection, location and identification by electric fishes is their electrosensory receptors and the This document is a typed, single-sided page from a report, identified as page "1". It contains an introduction titled "1. INTRODUCTION" and a section on "Communication". The text discusses electric fishes, their organs, and evolutionary aspects. There are no photographs, handwritten annotations, stamps, forms, diagrams, tables, or redactions visible on this page. The visual content is solely the printed text of the report. disturbance, also distinguishing between conductive and nonconductive objects. 4 -- ...~ -------·--'-- ___________ ..,... __ ,_ .,. ...... ------~-- ..... ---·· ..... -.-....... ---- ... _______ ... ----~~----·-- ·--····-.. In any case the key to the object detection, location and identification by electric fishes is their electrosensory receptors and the other lateral line detectors. The difficullies are multiple: some of the electric fishes are dif ficult to obtain; are susceptible to diseases; their nutritional requirement is not known; they are often injured and/or subjected to chemical treatments before shipment; and are intolerant of prolonged periods of coniined experi mentation. The Phase I Final Report \described the location and distribution of electroreceptors and a mech..'l.nical receptor of the lateral line system of the African fresh water weakly electric fish Gnathonemus petersii. The auto rhythmic activity of these electroreceptors has been recorded. The variation of the electric signal of the electric organ has been recorded for three speci mens of this species 'at rest activity and at the maximum signal rate. The number and density of different kinds of electroreceptors in the dermis were counted and their rate change sensitivity to a metallic object recorded. 5 --~~ --•---• ·~- --.,.-...,.__ *•--~~ ·-·---•·---.... '"" --... -·~•r 2. TECHNICAL DISCUSSION 2. 1 THE TRANSMITTING ELECTRIC ORGANS OF ELECTRIC FISHES 2. 1. 1 The Electromotive Force of Electric Organs In Figs. 1 and 2 some representatives of fresh water and marine electric fishes and their electric organs are shown. Electrophorus electricus and Malapterurus electricus are fresh-water strong electric fishes, the first one attaining a maximum discharge voltage from its main electric organ in excess of 600 volts, the second one only 300 volts. Torpedo nobiliana may discharge a train of pulses close to 220 volts and Astroscopus guttatus may attain 50 volts. The latter two are marine strong electric fishes. Gymnarchus niloticus, Gnathonemus petersii and Sternarchus albifrons are fresh water weakly electric fishes. Raja clavata is a rajid marine weakly electric fish. The electric discharge of some weakly electric fishes out of water may attain 7 to 8 volts, but in the water their voltage is attenuated to less than one volt in the immediate vicinity of the fishes. - -~~:---....... ·'\ 2. 1. 2 The ·waveform of Electric Signals Figures 3 and 4 show the pulse shape and duration of some species of electric fishes. Every species has its own characteristic electric discharge. Electrophorus is attenuated to less than one volt in the immediate vicinity of the fishes. - -~~:---....... ·'\ 2. 1. 2 The ·waveform of Electric Signals Figures 3 and 4 show the pulse shape and duration of some species of electric fishes. Every species has its own characteristic electric discharge. Electrophorus electricus has three electric organs: the main electric organ, the organ of Hunter and the organ of Sachs. The main electric organ and the spinal cord of Electrophorus are represented in Figs. 5 and 6. 6 • . 1/tUiP.tC CA.I,A!I / Fig. 1. Principal representatives of fresh-water electric fishes. Arrow indicates direction of current in the electric organs. = E Electrophorus electricus (electric eel) = G Gymnarchus niloticus = P Gnathonemus petersii (elephant-nose) = S Sternarchus albifrons (biack-ghost) = M Malapterurus electricus (electric catfish) 7 Fig. 2. Principal representatives of marine electric fishes. Arrow indicates direction of current in the electric organs. = R Raja clavata (thornback ray) = T Torpedo nobiliana = A AstroscoptlS guttatus (stargazer) 8 .. .. ---. .... ___ ,.. ...... "'~..,..·---·~-....---...&·~-~--....-----·---"'-~"''"'"----··----·- ------·-------~--------------~-------- ---~ ~~~·~------ ---~---·-- + 0 ~-3 ._I . I ms Gymnotus st; · · Gnathonemus s;.. + + l > 0 0 ~7 l \7 ~2res~. 10~ / ·ma ., !\lormYr\:s S'tt Eigenma."'lnia and Sterno?;,:~~ Fig. 3. Pulse shape and pulse duration of some species of electric fishes. 9 ..- -.;.,..,.-..., -r-.--.------.··--------......-... ... .,-_.....,_,._ .. ._.__---.. __. - --.. --...- _,..,,_ __ _.._._._. ___ ... .....,....,. .. .... _:-... "-"~-- -.~ .....,._...._._~---.-- ~_..-,_.___.,.- J<.>..-~·•·•..,... """'""! ' _}\__ H;popomus IP.I . G······· ... ·-:;:----- 1111 A 1 1 r ... J 'm~\:(. s: Hypo;~om11S IP.2 -~. ............. ~- r Stoetoqencs sp, ~l£'5'--- ·,s::; ... ::;;;_o /IIIII I /1 11111111111/11 I I TIITi IIIII/I I lldllllllllllllll ~ ---.~r:-,tm~t(. Sternopyqus IP, ~~=:::=::--=r w~uJ~::N:~w1~::!1N~NNN~w~\\W ~ , 'mltl .\J'Jv ... ;~, Fig. 4. Discharge of electric organs of some Gymnotidae, Sternarchidae and Ramphichthydae (redrawn after Hagiwara and :rvrorita(54)). 10 ·- Fig. 5. Tridimensional section of an Electrophorus electricus (electric eel) main electric organ, to show schematically the trajectory of the electric nerves (N) from the big spinal cord cells (M) to the posterior of the electroplates (E). Only a few electroplates are shown (redrawn after A. Fessard (18)). M H Fig. 6. Spinal cord of Electrophorus electricus showing the big cells of the electric neurons (M). 11 2. 1. 3 The Structure of the Electric Organs · . The document consists of typed text on a plain white page, with a single page number "2" at the bottom center. The text discusses electric fish communication and the related scientific research. There are no photographs, stamps, forms, diagrams, tables, or redations visible. The only handwritten mark is a single diagonal line / next to "a final report." The image displays a declassified page of text from a document. There are handwritten annotations present, including a checkmark in the top right corner and a line with a checkmark below the word "patterns." A circled number "3" appears in the bottom center of the page, likely indicating a page number. No photographs, stamps, forms, diagrams, tables, redactions, or visual evidence of experimental procedures are visible. cells (M) to the posterior of the electroplates (E). Only a few electroplates are shown (redrawn after A. Fessard (18)). M H Fig. 6. Spinal cord of Electrophorus electricus showing the big cells of the electric neurons (M). 11 2. 1. 3 The Structure of the Electric Organs · . The electric organ of Gymnarchus nil otic us is shown in Fig. 7. The electric organs of most electric fishes are derived from muscle tissue. Sternarchus albifrons is an exception. Its electric organ is derived from nervous tissue (Fig. 8). The electric organs of Mormyrus oxyrhyncus and Gnathonemus senegalensis are represented in Fig. 9 and 11. The elementary units or building blocks of electric fishes are called electroplates (or electro plaxes or electrocytes). Some mormyridae electroplates and their in nervation are shown in Fig. 10, 12 and 13. 2. 1. 4 Chemical Composition of the Chemotransmitter and the Metabolisn1 of the Electrogenic Tissue The chemotransmitter in the electric organs of electric fishes derived from muscle tissue is acetylcholine and its hydrolysis enzyme acetylcholinesterase. The chemotransmitter involved in the electric organ of Sternarchus albifrons (derived from nervous tissue) is not known. " The electric organs of fish are an invaluable tool for studying the-/ \ biochemical mechanism underlying bioelectricity. The organs are the most~ / powerful bioelectric generators created by nature and, moreover, highly ·~ j specialized in their function. Most of the electric organs of electric fishes l -. have unique structural features which permit the correlation of the electrical / · activity with the enzyme activity. (lO) ,- Choline acetylase in the presence of ATP (adenosine triphosphate) and of CoA is capable of synthesizing acetylcholine in solution. This enzyme is also present concomitant with acetylcholineesterase in a great variety of conducting tissue, motor and sensory axons, vertebrate and 12 .. . ,. I , . Fig. 7. Transverse section of the posterior half of a Gymnarchus niloticus. The section of the eight electric organs are shown (EE 1 to EE a)( redrawn after Fritsch). ._ Fig. 8. Tridimensional structure of the electric organ of Sternarchus albifrons. 13 ·- Fig. 9. Mormyrus oxyrhyncus: Caudal cross-section. The four black sections are electric organs (redrawn after Marcusen). 14 Fig. 10. Semi-schematic representation of an electroplate of Gnathonemus numenius. Orientation antero-posterior. (After Th. Szabo - Report to the French Academy of Sciences.) pl = anterior fold p = papilla 15 Fig. 11. Gnathonemus The image displays a scanned page of a declassified document, with primarily typed text. There are no photographs, signatures, stamps, or forms visible. Two instances of thick, black, hand-drawn brackets in the right margin suggest annotations or emphasis on specific sections of the text. There is also a page number "4" at the bottom center of the page. The text itself discusses a hypothesis about underwater pattern recognition systems in electric fish and proposes potential methods for simulating such systems. There is no visual evidence of e