. Electro-physiology. Electrophysiology. fact that the electrical organs of Gymnotus extend to the tip of the tail, we find ganglion-cells of the electrical type as far as the end of the spinal cord, but they gradually diminish in number and size, and more nearly resemble in form the ordinary motor cells of the anterior horn. While in these cases we have in Torpedo and Gymnotus electrical organs of such high differentiation that even the most powerful effects seem tib initio to be accounted for, there are in the tail of the common Skate (Rajct), as well as in the species of Mor- myrus, organs
. Electro-physiology. Electrophysiology. fact that the electrical organs of Gymnotus extend to the tip of the tail, we find ganglion-cells of the electrical type as far as the end of the spinal cord, but they gradually diminish in number and size, and more nearly resemble in form the ordinary motor cells of the anterior horn. While in these cases we have in Torpedo and Gymnotus electrical organs of such high differentiation that even the most powerful effects seem tib initio to be accounted for, there are in the tail of the common Skate (Rajct), as well as in the species of Mor- myrus, organs that in struc- ture and arrangement are unmistakably allied with the electrical, but of which the effects are so slight that they have only recently been de- termined. These du Bois- Keymond named " pseudo- electric " organs. This dis- tinction is, however, obsolete, •seeing that both Mormyrus and the various species of Raja belong to the true electrical fishes, so that, as Babuchin expresses it, " there are no pseudo-electrical fishes, but only large and strong, or small and weak, electrical fishes, ; As James Stark was first to discover, the electrical organs in the tail of Raja lie on either side, near the vertebral column, as two cylindrical, grayish, transparent bodies, pointed anteriorly and posteriorly. "They begin at the centre of the sacro-lumbalis muscle, near the junction of the anterior and second thirds of the tail, become gradually thicker, and, after completely displacing the muscle, lie close under the skin, where they are as thick as the muscle itself, and extend as far as the extreme end of the tail" (Fig. 245, a, I). Their position is shown even better in transverse than in longitudinal section (Fig. 246). Here the corn- position out of single, concentric " columns," running parallel with the axis of the tail, and separated, as in Torpedo or Gymnotus, by septa of connective tissue (M. Schultze's "primar
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