50 ON THE APPENDICES GENITALIAS (CLASPERS) IN THE SELACHIANS. 



also from & z ), and the fibres pass obliquely backward towards the last ray and the ventral marginal 

 cartilage. On the inside of this latter the muscle continues somewhat farther back, tapering, and 

 with the fibres running straight backward. The whole muscular wall may pretty easily be separated 

 from the two hindmost rays to which its fibres are not really attached; when thus separated from the 

 rays the whole muscular bag shows a rather strong resemblance to M. compressor in Chimmra. 



The M. dilatator is with the whole of its hindmost end attached to the covering piece 7', and 

 thus, by means of the firm connections of this piece with the distal end of the terminal part, it acts 

 on the movable portions of the terminal part 1 )- 



The glandular body is pigmented, and its longitudinal furrow runs a little obliquely; it 

 has before been briefly described by Leydig 2 ) and by Petri (I.e. p. 22), but none of these authors 

 mention the peculiar fact, in comparison with the /to/7-species (and accordiuglv it is to be supposed 

 that it has not before been seen), that the glandular body, continually tapering posteriorly, stretches 

 throughout the shaft quite down to the terminal part. In the shaft it follows the ventral mar- 

 ginal cartilage, and is here for some way along this skeletal piece surrounded by the outer lip- 

 muscle , the latter appearing as the continuation of the dorsal muscular wall of the bag . The 

 longitudinal furrow, and the openings in it follow the glandular body quite to its hindmost end. 



Torpedo oculata Belon. 



In this species the features are principally as in T. marmorata. 



In a specimen of a length of 30 cm , a breadth of ic/ m , the following measures were found: 



Length of the appendix 43" 



- - slit 36" 



part free of the fin 17" 



terminal part abt. 14" 



Breadth of the appendix 7 — 8" 



,min 



Vnm 



7111m 



, mm 



2mm 



Narcine sp. 



(PI. III. fig. 32. 340 



A badly preserved specimen, the species of which is difficult to determine, measures in length 

 24,5 cm , in breadth i2 cm : 



. The appendix from the beginning of the slit to the hindmost point is ... . 27 mm 



free part i4 mm 



length of the terminal part io mm 



breadth of the - c m "> 



■i Petri has given a very imperfect description of the muscles of which he only mentions M. di/atalor. (Comp. 1. c. 

 fig. 4 B and C. I 



2 ) Beitrage zur mikroskopischen Anatomie und Eutwickelungsgeschichte der Rochen und Haie, 1852, p. 86. 



