400 Analytical Synopsis of the Order of Squali. 



halves meeting at a more or less blunt 

 angle. Snout semioval. Isoplagiodon. 



EE. Teeth entire below ; above with the base 



coarsely serrated. Hypoprion. 



EEE. Teeth entire in both jaws. Aprionodon. 



DDD. First dorsal near the ventrals. Cynocephalus. 



BB. Teeth with one or two acute lateral denticles on 



each side. Tricenodontes. 



Nasal valves without barbels; tail pits developed. Tricenodon. 

 Nasal valves with well developed barbels ; tail 



pits none. Leptocharias. 



AA. Spiracles developed. 



B. Teeth with lateral denticles. Scylliodontes. 



Snout blunt. Eye-openings long, Triakis- 



BB, Teeth without lateral denticles, Galeorhini. 



C. Caudal furrows obsolete. Galeorhinus. 



CC. Caudal furrows above and below. 



D. Teeth denticulated on both edges. Under 

 caudal border with two notches. 

 Snout high, declining obliquely backwards. 



Tail forming about one-quarter of length. Boreogaleus. 

 Snout produced and depressed. Tail forming 



one-third of length. Galeocerdo. 



DD. Teeth triangular, without a ledge, serrated. 



Caudal fin only once notched. Thalassorhinus. 



DDD. Teeth without serrature internally. 

 Pupil convex above, pointed below. 



Rictus little convex. Teeth above with the 

 inner edge curved outwards ; outer con- 

 cave and serrated. Heraigaleus. 

 Rictus as long as wide. Teeth above with 

 the inner margin incurved ; outer with a 

 denticulated ledge. Chsenogaleus, 

 Pupil subcircular. Teeth not serrated. Loxodon. 

 11. Teeth flat and paved. Musteline. 

 Eye-openings long. Mustelus. 



