6 4 



ON THE APPENDICES GENITALES (CLASPERS) IN THE SELACHIANS. 



Two pairs of ventrals with fully developed appendices, now before me (unfortunately I cannot 

 give the total length of the animals) show the following measures: 



Length of the appendix io cm 



- part free of the fin 6,2 cm 



- terminal part 4,6 — 5™ 



Breadth of the 



2,7 cm at the broadest spot 



- basal part i,6 cm 



A dried specimen of a length of 39"", a breadth of 24 cm shows full)- developed appendices, 

 8 cm long, and 2,2 cm broad across the terminal parts; in another specimen (in spirit) 43 cm long, and 2o, cm 

 broad the appendices are only 6,5 cm long, the terminal part abt. 4 cni long, 2,i cm broad; here thev are 

 not yet fully developed though it was to be expected judging from the size of the animal. Facts as 

 these, that rather grown individuals have rather undeveloped appendices, I have ofteuer seen, for inst. 

 in Acanthias. 



The appendix is naked, much more clumsy than in the 

 preceding species, flattened, somewhat rounded on the dorsal side, 

 the contour is clumsily clubshaped; the club is formed by the 

 terminal part constituting more than half the length of the part 

 to be seen from the back. The appendix-slit runs from the fore- 

 most dorsal opening laterally, so that it cannot be seen from the 

 dorsal side except in the hindmost end of the terminal part, 

 where the dorsal lip, as it were, retires; the dorsal lip, throughout 

 the terminal part, is supported by inner skeletal parts reaching 

 to its edge, while the soft membrane of the ventral lip as a broad 

 wall stretches past its skeletal part (7" 1 ,), and is laid - in a 

 similar manner as in the Skate - - dorsally against the upper 

 lip; from the hinder, lateral edge of this latter a naked spine 

 projects. If the soft, ventral dermal lip vl is thrown back, an 

 elevated, long, bowshaped, cutting edge of the skeletal piece 7", 

 is laid bare (fig. 26 in the text, to the right of 61). If the term- 

 inal parts are opened still more (which here is easily done), we 

 shall, although with altered shapes and relations, see correspond- 

 ing projections and hollows as those described in R. batis and 

 clavata. The upper side of the piece T, does not here show (or 

 shows at most weak traces of) the transverse folds 61, peculiar in those two species; a broadly tongue- 

 shaped, rather soft and movable lamella with porous edge and spongy lateral surface represents 

 da in the Skate and the Thorn-back; a large, ovate, hard swelling corresponds to the process Tv 2 ; 

 behind and laterally of this the ventral recess Lv is found, large and deep; the foremost recess Ld is 

 smaller and more hidden, situated before the ovate swelling, and also the lamella Rd' supporting its 

 lateral wall, is only little conspicuous. 



-da 

 - T, 



vl 



bl 



To, 



Lv 



Fig. 26. 



Raja radiata. The terminal part of the 

 right ventral, much dilated; reduced. Td 2 

 the naked spine of this same skeletal 

 piece. The letters as in fig. 24 and 25. 



