8ELACH0IDEI. 355 



Fam. 4. NOTIDANID^. 



No nictitating membrane. One dorsal fin only. 

 No pit at the root of the caudal 19. Notidanus, p 397. 



Fam. 5. SCYLLIID^. 



No nictitating membrane. The first dorsal ^ above or be- 

 hind the ventrals ; an anal fin ; mouth inferior. Teeth small, 

 several series being generally in function, 



1. Nasal and buccal cavities separate. 



Upper edge of the caudal fin not serrated . . 20. Scylliwn, p. 400. 

 Upper edge of the caudal fin sen-ated .... 21. Pristiwus, p. 406. 



2. Nasal and buccal cavities conjlueiit. 



Spiracles minute, behind the eye; the second dorsal nearl_y opposite to 

 the anal 22. Gitiffh/mostoma, p. 407. 



Tail and caudal exceedingly elongate ; snout very obtuse. 



23. Stegostoma, p. 409. 



Spiracles minute, below the posterior angle of the orbit ; origin of the 

 anal in advance of the second dorsal . . 24. Parascyllium, p. 410. 



Spiracles very distinct, below the eye; anal placed far behind the second 

 dorsal ; sides of the head without appendages. 



25. Chilosci/llium, p. 410. 

 Spiracles wide, oblique slits ; sides of the head with skinny appendages. 



26. Crossorhiiius, p. 413. 



Fam. 6. CESTRACI0NT1D.E. 



No nictitating membrane. Two dorsal fins, the first opposite 

 to the space between pectoral and ventral fina ; an anal. Nasal 

 and buccal cavities confluent. Teeth obtuse, several series being 

 in function. 



Spiracles small, below the eye 27. Cestracion, p. 415. 



Fam. 7. SPINACID^. 



No nictitating membrane. No anal fin. Pectorals not notched 

 at their root. Snout without lateral armature. 



1. Each dorsal Jin with a spine ; a fold of the skin running alotig each side 



of the belly. 



Trunk elevated, triedral 28. Centrina.^ p. 417. 



2. Each dorsal Jin with a spine ; nolateral fold of the skin. 



Teeth equal in both jaws, oblique 29. Acanthias, p. 417. 



Upper teeth erect, with a single cusp ; lower more or less oblique. 



30. Ccntrophorus, p. 419. 

 2 A 2 



