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University of Califoniia Publications in Zoology [Vol.16 



(ba.p., text-fig. G) which bears one or two small terminal segments. 

 From this in the female proceed twenty-one or twenty-two radials, all 

 of which excepting the last five are segmented. Anteriorly a much 

 enlarged plate strikas the basal piece, forming an obtuse angle. From 

 this also run three rows of radials. At the proximal end of this 

 enlarged plate and the basal piece are the two fossae with which the 

 protuberances from the pelvic girdle above described articulate. 



Pigs. G aiul H. Pelvic fin of male and female, Hcptanclms macidatus (XI). 

 Dorsal view. 



j3., the beta cartilage; h^'-., connecting segments; ba., basal piece; ha.p., basi- 

 jiterygium; pL, pelvic girdle. 



In the male (text-fig. H) the long basal piece is continued by the 

 axial cartilage of the claspers (ba.). Where the two join there are 

 two segments 6^'- and dorsal to these is the so-called /S cartilage. 

 Distally on the main axis I was unable to find the blade-like terminal 

 cartilages described by Krall (1908) for Hexanchus, but this is prob- 

 ably due to the fact that tlie specimen from which text-figure H was 

 taken was small. 



The pelvic girdle (pi., text-figs. G and H) consists of a flattened 

 band of cartilage slightly concave dorsally and enlarged at the ends. 



