404 Analytical Synopsis of the Order of Squali. 



Family NOTIDANOID^. 



Synopsis, 

 Branchial apertures 6. Hexanchns. 



Braiicliial apertures Y. HeptrancLias. 



Genus Hexanchus Raf., 1810. 

 Monopterhinus Blahiville^ 1816. 

 Kotidanus Cuvier, 1817. 



Type Hexanchus griseus Haf 



Genus Heptranchias Raf.^ 1810. 

 Heptanchns Mull, and Henle, 1838. 

 IS^otorhynchus Ay res, 1855 (N. maculatus Ayres). 

 Type Heptrancliias cinerens Jiaf. 



Family SPINACOID^ Owen. 

 Synopsis. 

 A, Teeth of lower jaw subquadrate, with a nearly hori- 

 zontal incisorial edge, and a point directed outwards. 

 B. Teeth of upper and lower jaws similar. Scales 



cordiforra. Squalus. 



BB. Teeth of jaws dissimilar. 



C. Branchial apertures equidistant. 



Teeth of upper jaw with a large conical median 



cusp and two smaller ones on each side. Spinax. 



Teeth of upper jaw slender, conic, and little inci- 

 sorial. 

 CC. Branchial apertures behind (4 and 5) approxi- 

 mated. Scales cordiform. Oxynotus. 

 Teeth of upper jaw triangular, on a quadrangular 



base. Centrophorus. 



AA. Teeth of lower as well as upper jaw straight, pointed, 

 and with one or two smaller cusps on each side. 

 Scales pointed, with a stellate base. Centroscyllium. 



