ELECTRICAL FISHES 



401 



compartment, while the anterior surface, presenting many in- 

 equalities, is free, and turned towards the head-end of the fish ; 

 it is separated by a small fissure filled with gelatinous substance 

 from the anterior wall of the next compartment (Fig. 260). 

 From the front aspect, each plate appears as a fairly circular 

 disc, its central point being marked by a shallow prominence, 

 giving origin to several high radial folds, while there is a corre- 

 sponding depression on the posterior surface, from the founda- 

 tion of which springs a kind of stalk connected with the ingoing 

 nerve-fibre (Fig. 260, N P l ). 



K 



I: 



-.X-. < 5 



FIG. 261. Malapterurus. Medium portion of a plate (PI) with nerve-stalk (ne), under high 

 power. (Fritsch.) 



The substance of the plates, which increases in diameter with 

 the size of the animal, is homogeneous and transparent in the 

 fresh condition (Fig. 261). Eounded nuclei are embedded at 

 regular and tolerably wide intervals, and were taken by Babuchin 

 for star-shaped cells, with fine, hair-like processes. According to 

 Fritsch, on the other hand, each electrical disc must be regarded 

 as a multinuclear protoplasmic body, a kind of " giant electrical 

 cell." 



The marginal striation first observed by Eemak on the plates 

 of Torpedo occurs also on the discs of Malapterurus, and is 

 ascribed by Fritsch to a peculiar porosity of the most external 

 layer of the plate-substance (Fig. 261). The "rods" enclosed 



VOL. II 2 D 



