296 ELECTRICAL ORGANS IN FISHES. 



the discs ; the former on the concave, alveolar, or posterior 

 face ; the latter on the convex, smooth, anterior face : and, like 

 the vascular and nervous trunks and branches of the organ, 

 lie in the midst of the areolar texture, which forms the 

 greater and lesser laminae of separation and connection of the 

 constituent series and discs of the battery. The ultimate 

 arterial twigs enter the areolar texture which lines the con- 

 cave face of each disc ; and pass into the alveoli as bundles 

 of looped capillaries, which are continued into similarly 

 arranged venous radicles. A number of ultimate nervous fila- 

 ments spread from one of its margins through the areolar 

 lamina, which clothes the convex face of each disc, preserving 

 their double contours, until, becoming somewhat narrower, 

 they divide into two or three secondary filaments, which, 

 assuming an elongated fusiform aspect, and enclosing a 

 nuclear mass, pass into corresponding secondary divisions of 

 neighbouring filaments. The smooth convex surface of each 

 disc is thus covered by an areolar lamina, which contains a 

 network of ultimate branching and anastomosing nerve-fila- 

 ments ; the secondary or division filaments, which form the 

 boundaries of the meshes of the network, having a peculiar 

 festooned or looped fusiform aspect, with a mass resembling 

 a nucleus in the centre of each. 



This organ bears a resemblance to the batteries of Torpedo, 

 and more particularly to those of Gymnotus, in the peculiar 

 relations of the nerves, vessels, and nucleated texture ; and if 

 an electrical current exists in certain circumstances (pro- 

 bably when the animals are in season), it must pass in a 

 contrary direction to that of the Gymnotus that is, from 

 tail to head. 



These organs in the tail of the rays were discovered by 

 Dr. Stark of Edinburgh ; and their relative and general struc- 

 ture, as well as their probable function, described in an able 

 paper read to the Eoyal Society of Edinburgh in 1844 (Pro- 



