ON THE APPENDICES GENITALES (CLASPERS) IX THE SELACHIANS. 



The exterior of the appendix is chiefly as in Torpedo; we find hen- the same marginal slits 



(and pockets |, but the medial one is with the buttonhole shaped, distal part situated quite on the 



dorsal side, and the lateral one is turned a little ventrally; next it is to be 



remarked that the appendix-slit in the whole of the free part of the organ is 



lying quite laterally, the dorsal lip overlapping it quite to the outer edge 



like a cover, much broader than in Torpcdo\ corresponding to this the portion 



of the terminal part containing the piece Td is folded quite over the hindmost 



part of the appendix-slit. The glandular bag and its inner gland are relatively ' \ / 



more strongly developed than in Torpedo. 



Td 

 In the skeleton, notwithstanding the principal conformity with Torpedo^ 



Fig 



several peculiar features are found. Between the basale and the appendix- 



Nart ine sp. The i 

 stem also here two pieces, b x and o 2 , are found, the former short, the latter appends the 



longer; o z bears the last ray at the connection with the basale; the last rav 



size. / the opening 

 but one seems to me only to articulate with the basale. The piece /9 is to- the medial pocket 



tallv wan tint;-. The appendix-stem is longf, considerably lonerer than the ba- 



° 1 l & . & vered by the skin. 



sale + b z and b z \ it is calcified in the surface excepting the short end-style, 



which distally becomes broad, flat, with rounded hindmost contour. The marginal cartilages are thin, 

 rather short, and occupy only the hindmost half of the stem; the ventral one shows the same features 

 as in Torpedo; also here it reaches a little farther forward; the dorsal one, when seen from the dorsal 

 side, forms a broad, ovate leaf tapering proximally, and continuing as an uncalcified band quite to 

 the articulation of the appendix-stem with b 2 ; its lateral edge reaches to the free edge of the ventral 

 marginal cartilage; seen from the ventral side it is hollowed in a trough-like manner as in Torpt 

 but distally it does not nearlv reach so far as in the latter, and consequently the two marginal car- 

 tilages do not end so obliquely of each other distally (this fact seems also to imply a greater mobility 

 of the terminal part in Narcine than in Torpedo). 



The number of terminal pieces is three, to which is to be counted a quite similar ventral 

 covering piece v as that in Torpedo. As already mentioned, Td is folded to the dorsal side, and has 

 apparently a shape deviating considerably from that found in Torpedo\ a closer examination sli 

 however that this deviation to some degree is due to the position; on the medial-dorsal side the piece 

 is hollowed in a groove-like manner (for the medial marginal slit |; otherwise it is flatly rounded 

 on the outer surface, concave towards the appendix-slit, with a sharp lateral, convex edge. 



Tv is short, oval, rounded towards the appendix-slit (as in Torpedo) concave on its outer sur- 

 face, by which, together with the covering piece v, it forms the hollow for the lateral pocket . 

 is somewhat s-shaped, tapering to both ends, little and slender. The covering piece is chiefly as in 

 Torpedo; also here we find on both its margins curvatures destined (especially on the lateral margin) 

 to form the button-hole shaped opening of the pocket together with the terminal pieces Td and 

 The foremost lateral corner appears independent as a very small :•'. 



The muscular system is as in Torpedo with the exception that the part of the ill. com- 

 pressor that may be seen on the ventral side, is relatively larger, and laterally spreads somen 



