4 



*& 



% 



J* 



 kr-' 



s 



r  ••-" 



I 1 mm. 



"*~" 



C L. 





Figube 7. — Camera lueida drawings of denticles from some western Atlantic catsharks : A, Scyliorhinus 

 meadi from 264-mm. immature male; B, Apristurus prof undo rum from 380-mm. immature female; C, 

 Scyliorhinus torrei from 243-mm. adult male; D, Scyliorhinus hesperius from 296-mm. immature male; 

 B, Apristurus riveri from 450-mm. adult female ;• F, Schroederichthys maculatus n. sp., from 295-mm. adult 

 female ; G, Scyliorhinus retifer from 410-mm. adult male ; H, Galcus arae from 287-mm. immature 

 female. Note : Denticles of Apristurus profundorum are more erect over most of the body surfaces than 

 shown here, their points projecting almost perpendicularly from the plane of the skin surface. 



sides of the middorsal line of a 160-mm. specimen 

 of CephaloscyUiwrn uter from Monterey Bay, 

 Calif. 



Teeth 



The teeth of scyliorhinid sharks are small, most 

 commonly with a larger central cusp having one 

 or more smaller lateral cusps on each side. In some 

 species of Apristurus the teeth nearer the corners 

 of the mouth may have many cusps (as many as 

 nine have been noted) with the central cusp but 

 little higher than adjacent ones. In Atelo- 

 nvycterus from the Indo-Pacific, the cusps of some 

 of the teeth near the corners of the mouth are 

 much reduced and the rows are fitted so close to- 



gether as to form an almost smooth grinding sur- 

 face. 



Except for specimens of Apristurus, the tooth 

 form does not vary greatly in the scyliorhinid 

 specimens examined from the western Atlantic 

 and it is probably impractical to attempt to dis- 

 tinguish most species from teeth alone. Western 

 Atlantic Apristurus, as a general rule, have teeth 

 with more cusps and, in some Apristurus, crowd- 

 ing of some of the lateral cusps in front of the 

 central cusp (see fig. 9D) is frequent. 



In Apristurus riveri the most extreme tooth 

 dimorphism yet reported for sharks occurs. The 

 two adult males that constitute our entire series of 



REVIEW OF WESTERN ATLANTIC CAT SHARKS 



591 



