XI 



ELECTRICAL FISHES 371 



(Fig. 239), increasing posteriorly, so that it soon occupies the 

 upper half of the total diameter of the organ, and finally pushes 

 its way completely behind the large organ. A section parallel 

 with the long axis of the fish shows a general fusion of the 

 longitudinal septa between the wide-spaced columns, which end 

 before and behind in sharp wedges (Fig. 240, I) ; the cross- 

 section is spindle-shaped, or rhomboidal. 



If a longitudinal section of the electrical organ (parallel 

 with the axis of the organ, and vertical to the long partition walls) 

 is examined under a high power, it is easy to see the cross-sections 

 of the transverse septa of connective tissue, extended between 

 each pair of longitudinal partition walls, together with the com- 

 partments which they enclose, each containing a transversely 



FIG. 240. a, Portion of several superposed prisms of Gymnotus (two wide compartments below). 

 (Pacini.) b, L.S. through prisms of Gymnotus, wide and narrow compartments. (Du Bois- 

 Reymond.) 



bisected electrical plate (Fig. 241). With regard to the position 

 and mode of attachment of the latter, there is a fundamental 

 difference between Pacini and M. Schultze (31), as appears from 

 the two figures (241, a, I). While Pacini holds that the plates 

 depend freely in the compartment, and are attached only at the lon- 

 gitudinal septa, Schultze maintains that each transverse partition 

 wall (6) coheres with the posterior surface of the corresponding 

 plate, so that there is a space only in front of, and not behind it. 

 Both anterior and posterior surfaces of the plate are thickly set 

 with papillse ("villi," M. Schultze), behind which there are 

 posteriorly, thorn-like processes (prolnngamenti spiniformi, Pacini), 

 which extend to the posterior partition wall, and are attached there. 

 Schultze failed to discover the latter, while Sachs confirmed the 

 observations of Pacini, as also for the cleavage of the plates (as 

 observed by the latter), into an anterior and a posterior half. He 

 regarded the papillae with their so-called " nuclei " (known later 



