in having a reduction (in the. larger specimens ex- 

 amined) in the number and size of the accessory 

 cusps on the teeth of the lower jaw. 



In many features the Halaelwrus of the southern 



part of South America resembles Schroederieh- 

 thys. Dr. Elvira Siccardi who has examined 

 many specimens from Argentina has called my at- 

 tention (in personal communication) to several 



Figure 27. — Photographs of lower side of heads: A, Scyliorliinus torrei; B, Scyliorhinus retif&r; C, Scylior- 

 hinus meadi; D, Scyliorhinus hesperius; E, Scyliorliinus boa; F, Galeus arae; G, Galeus cadenati; H, 

 Galeus arae; I, Apristurus profundorum; J, Apristurus riven; K, Apristurus laurussoni ; L, Apristurus 



indicus. 



REVIEW OF WESTERN ATLANTIC CAT SHARKS 



617 



