CHLAMYDOSELACHIDAE. 13 



snout depressed; spiracle present or absent; a nictitating fold 

 teeth in bands or pavements, more than one series in function 



Galeorhinidae (page 162) 



Centracoidei. 



Two dorsals each with a fixed spine; an anal; spiracles; nasoral grooves 



snout short; mouth narrow, lobed and folded; caudal short, axis raised 

 teeth raptorial in front, molarial backward 



Gentraciontidae (page 180) 



Squaloidei. 



Two dorsals each with a spine; no anal; spiracles; no nasoral grooves 



snout moderate to long; mouth protrusible, with a deep groove at each angle 

 teeth compressed, sectorial to cuspidate . . Squalidae (page 188) 

 Two spineless dorsals; no anal; no nictitating fold; spiracles present 



snout short; tail without pits or keels; mouth inferior, with grooves and 

 folds 

 teeth raptorial on upper jaw, sectorial on lower 



Scymnorhinidae (page 233) 

 snout short, broad; dorsals small, behind the body; caudal axis raised 

 teeth sectorial on both jaws; no nasoral grooves; 



Echinorhinidae (page 242) 

 snout greatly produced, with sharp teeth on its edges and with barbels 



teeth on the jaws small, a number of series in function; 5-6 gill openings 



Pristiophoridae (page 244) 



Rhinoidei. 



Two dorsals, without spines; no anal; head and body depressed 



snout very short; pectorals expanded, free from the head; dorsals on the 

 tail 

 mouth wide, anterior; spiracles present; tail keeled at each side 



Rhinidae (page 248) 



CHLAMYDOSELACHIDAE. 



Body elongate, slender. Head broad, depressed. Eyes lateral, without a 

 nictitating membrane. Nostrils distinct from the mouth. Mouth anterior, 

 without labial folds; teeth with broad, backward-extended bases and slender 

 cusps. Spiracles small. One dorsal, not preceded by a spine. An anal fin. 



