6o 



ON THE APPENDICES GENITALES (CI.ASPERS) IN THE SELACHIANS. 



to the accompanying figures, and in these the total want of letters indicating the single parts; still 

 later they have been described by Petri') and Moreau^). Besides short remarks on these organs 

 are found in several writers of mostly systematic works. None of these descriptions seem to me to 

 be quite serviceable. 



In a specimen of the total length of "jG""" the whole length of the appendix is 18"='". The other 

 measures are: 



Length of the free part 13''"' 



from the fore end of the slit to the extremity of the appendix 15'^"' 



from the fore end of the terminal part 10'^"' 



Largest breadth (across the base of the terminal part) . . 2,7'"" 



The whole appendix is naked (but on the abdominal side of 

 the glandular bag are found some scattered thorns); the shape is 

 lengthened-clavate with a short shaft; the terminal part forms the club, 

 and is relatively very long, broadest at the base, and tapering from 

 thence towards the point. Onh* the foremost dilatable part of the 

 appendix-slit, the part forming the foremost outlet from the glandular 

 bag, is situated dorsally; from here the slit goes laterally, almost 

 even passing to the ventral side; from this side it can be seen, but 

 not at all from the dorsal side (contrary to the situation in the Skate). 

 This is brought about bv the fact that the dorsal lip, which only 

 proximally is supported by skeletal parts, at the base of the terminal 

 part overlaps the slit to such a high degree; the ventral soft lip is, 

 when compared to that of the Skate, only very narrow. If the term- 

 inal part is opened so much, that the interior is seen J), this latter will 

 present an appearance, apparently quite different from that in the 

 Skate; it will, however, be possible to point out quite corresponding 

 projections and hollows: on the ventral side of the slit is seen, rela- 

 tively only little conspicuous, the membrane-covered terminal piece Z'34) 

 which shows before a sharp, cutting edge, and on closer examination 

 also is seen, as in Raja bafis, to bear on its upper surface a row of 

 transverse, soft, but less developed dermal leaves bl\ a bayonet- 

 like, hard, and sharp-edged blades) (on which one may easily cut one- 

 self, although it is covered by membrane) projects strongly, correspond- 

 ing to 77^2 in the Skate; to the piece 77' in this latter corresponds a 



Fig- 25. 



Raja clavaia. The terniinal part 



of the right ventral appendage, 



much dilated ; reduced. The letters 



as in fig. 24. 



') 1- c. p. 310. 



2) Hist. nat. des Poissons de la France, vol. I, 1881, p. 24S — 259. 



3) Petri, I.e. pi. XVI, fig. i D, has given a drawing of the dilated terminal part, which is quite unsatisfactorj', 

 especially with regard to the ventral side. 



4) Petri, 1. c. fig. i D, hk. 



5) Petri, bj. 



