SEXUAL CHARACTERS — ELASMOBRANCH FISHES 



227 



epithelium lining the sac is the best example at present seen of 

 the stratified variety, comprising four or five rows of cells, with 

 an occasional mucus-secreting cell, as in Galeus. I should 

 consider that in this type the siphons are the best adapted to 

 perform the normal functions assigned to those organs. 



Fig. 7 Centrophorus lusitanicus. CL, clasper; A., apopyle; S., siphon 

 CENTROPHORUS LUSITANICUS 



The Portuguese arreghonda 



This sexually immature specimen, measuring 72 cm., taken on 

 the coast of Portugal, shows a strong resemblance to Spinax in 

 the following points (fig. 7) : 



The claspers are short, adnate with the pelvic fins; but there 

 are no spines present in this specimen. The apopyle is wide with 

 a tumid border. 



