. Elements of the comparative anatomy of vertebrates. Anatomy, Comparative. Jl- TM- Monnyridse, for example, there is on each side an vipper and lower row of electric organs. The electric apparatus in all the above-named Fishes is to be regarded from the same point of view both as concerns its mode of development and its anatomical relations : all electric organs are to be looked upon as consisting of metamor- phosed muscular fibres and the nerve-endings belonging to them as homologues of theraotor end-plates which are ordinarily found on muscles. As regards the structure of the elec- tric org
. Elements of the comparative anatomy of vertebrates. Anatomy, Comparative. Jl- TM- Monnyridse, for example, there is on each side an vipper and lower row of electric organs. The electric apparatus in all the above-named Fishes is to be regarded from the same point of view both as concerns its mode of development and its anatomical relations : all electric organs are to be looked upon as consisting of metamor- phosed muscular fibres and the nerve-endings belonging to them as homologues of theraotor end-plates which are ordinarily found on muscles. As regards the structure of the elec- tric organs, tlie same essential arrange- ments are met with in all: the details of their histology ami physiology cannot be entered into here. The framework is formed of fibrous tissue en- closing numerous cells, which, running partly longitudinally, partly transversely through the organ, gives rise to numerous poly- gonal or more or less rounded chambers or compartments. These latter are arranged in rows, either along the longitudinal axis of the body (Gymnotus, Malopterurus) or in a dorso-ventral direction (Torpedo), forming definite prismatic columns (Fig. 120). Numerous vessels and nerves ramify in the connective-tissue lying between these compartments, the nerves being enclosed in thick sheaths, and having a different origin in the different forms. In Torpedo, in which the electric organs probably arise muscle of the mandible. Fig. 119, A and B.—The Electric Organ of Gymnotus electricus. (B, from a preparation by A. Ecker.) H, skin ; Fl, fin ; DM, D3P, dorsal portions of the great lateral muscles, seen partly in transverse, partly in longitudinal, section; VM, VAP, ventral portions of ditto ; 111, the electric organ, seen in transverse section at E (B), and from the side at S^; WS, vertebral column from the side, and the spinal nerves, and WS', in transverse section; LEC, posterior end of body cavity; Sep, median longitudinal fibrous septum between the left and right electric o
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectanatomycomparative
