SQUALID^. 



157 



Notidanus (Cuv.). One dorsal, over the anal ; 

 teeth, of the upper jaw triangular, of the lower jaw 

 saw-like ; six gill-openings. 



N. griseus. Fig. 233 ; ^n.s. 



Mustelus (Cuv.). Smooth Hound. As Galeus, 

 but the teeth are flat, as in the Raiada. 

 M. Isevis. Fig. 234 ;..*. 



Zyg&na (Bisso). Hammer-head. Head flat, 

 produced on each side, with the eyes at the ex- 

 tremities ; fins as in Galeus. 



Z. malleus. Fig. 235 ; $ n. s. 



