8EI,ACnOIDEI. 355 



Fam. 4. NOTIDANID^. 



No nictitating membrane. One dorsal fin only. 



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



Fam. 5. SCYLLIID^. 



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

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

 several series being generally in function. 



1. Kasal and buccal cavities scjyaratc. 



Upper edf^e of the caudal fiu not serrated . . 20. Scj/Jh'inn, p. 400. 

 Upper edge of the caudal fin serrated .... 21. Fristiurus, p. 400. 



2. Nasal and buccal cavities confluent. 



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

 the anal 22. Ginghimostoma, p. 407. 



Tail and caudal exceedingly elongate ; snout very obtuse. 



2.3. 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. Chiloscyllium, p. 410. 

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



26. Crossorhinus, p. 413. 



Fam. 6. CESTRACIONTID/E. 



No nictitating membrane. Two dorsal fins, the first opposite 

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

 and buccal cavities confluent. Teeth obtuse, several series being 

 in function. 



Spiracles small, below the eye 27. Cestracion, p. 115. 



Fam. 7. SPINACID.^. 



No nictitating membrane. No anal fin. Pectorals not notched 

 at their root. Snout without lateral armature. 



1. Eachdorsalfln icith a spine ; a fold nfthcslin running along each side 

 of the belly. 



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



2. Each dorsal fln with a spine ; nn lateral fold of the skin. 



Teeth equal in both jaws, ol)lique 29. Acanihias, p. 417. 



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



30. Centrophoriis, p. 419, 

 2a2 



