ON THE APPENDICES GENITALES (CLASPERS) IN THE SELACHIANS. 



43 



aperture (at /') leading into a «pocket between the ventral terminal piece [Tv) and the ventral 

 covering piece ;■'. 



If the lateral lip of the appendix-slit above the terminal part is lifted, a thick glandular 

 body is seen protruding from the medial side of the canal, in which feature this species differs from 

 all other Sharks I have had the occasion to examine. This gland will he more particularlv mentioned 

 afterwards. 



The skeleton. Between the basale and the appendix-stem three short pieces (/^i , />,, and ^,) 

 are found, each bearing one of the three hindmost rays (the two hindmost of these rays are termin- 

 ally quite coalesced for a long way). At a first glance the piece /9 seems to be wanting, but a closer 

 examination shows it to be present, represented by a little cartilage, arising from the lateral hind 

 corner of /',, and joined by a particular articulation to the proximal end of the appendix-stem />. Con- 

 trary to what commonly is the case in the Sharks, the piece y? does not here articulate proximallv 

 with the basale. 



The appendix-stem (d) is long, considerably longer than the basale (the ratio is s/^), round 

 (with the exception of the proximal part where it dorso-ventrally is somewhat flattened); the style is 

 long, not, however, reaching to the hindmost point of the terminal part. The marginal cartilages are 

 short, and are onh- foimd at the distal part of i; contrary to what commonly is the case in the 

 Sharks, the ventral marginal cartilage is the one reaching most forward. The general shape of 

 these cartilages, I think, may be seen with sufficient clearness from the figures. The ventral marginal 

 cartilage bends towards the dorsal one with a j^late similar to that found in many other Sharks, but 

 does not quite reach it. But this plate is here in a peculiar way hollow, being behind split into two 

 lamellae receiving between themselves the proximal end of the piece Tt'; this piece, then, projects into 

 the ventral cartilage, quite covered, until the point marked « in fig. 25 "). The hindmost end of the 

 inner one of these two lamelke protruding very much, the appendix-slit is by its transition to the 

 terminal part straightened to an extraordinarily narrow passage. 



The number of terminal pieces must in reality be taken to be four; but to these four is 

 added a good-sized, ventralh- situated piece, 7', rounded in a scutiform manner, and partly covering 

 the terminal part (see fig. 24) behind the ventral marginal cartilage. This piece has develoj^ed in the 

 aponeurosis which, in the Sharks hitherto mentioned, encloses the terminal part, and it serves like 

 this aponeurosis for inserting the large J/itsc. dilatator. If this piece v is removed, the ordinary ter- 

 minal pieces are easily recognized: Td which is rather broad, flat, with a thickened edge medially 

 (which edge follows the st}'le closely, but reaches a little further backward), and a sharp and thin 

 edge lateralh-; Td^ proximally joined to the foregoing piece, is a broad, but thin, and but slightly 

 calcified lamella. Tv is of a very peculiar shape, thick and solid, ventrally rounded, dorsally, towards 

 the slit, deeply hollowed in a spoon-like shape; its proximal end, as already mentioned, passes its arti- 

 culation with Rv ^ and enters between the two lamellce of the overlapping jjlate; with the proximal 

 end articirlates, completely hidden, a little calcified piece representing the <thorn> or <spur , 7^,; this 

 latter piece (see fig. 27) is proximalh' irregularly head-shaped, and from this thick part a thinner one 



1) If in Acaniliias or Spi'uax tlie projection of tlie ventral marginal cartilage, mentioned at p. 28, was more developed, 

 and proximally prolonged, a similar state of matters might be the result. 



6* 



