356 SELACHOIDEI. 



Upper teeth erect, tricuspid, the lower oblique. 



31 . Spinax, p. 424. 

 Teeth equal in both jaws, very small, tricuspid. 



32. Centroscijllium, p. 425. 



3. Dorsal Jins withotd spine: the first conspicuoush/ in advance of the 



ventrals. 



Dorsal fins equally short. Lower teeth erect, triangular. 



33. Scymmis, p. 42o. 

 Porsal fins equally short. Lower teeth oblique, truncate. 



34. Lcemarrixis, p. 42G. 

 The second dorsal much longer than the first. 



35. Eiiprotomicrus, p. 427. 



4. Dorsal fins without sjrine ; the first opposite to the renirals. 



Teeth equal in both jaws, large, very oblique, denticulated. 



36. Dchinorhintis, p. 428. 

 The lower teeth much larger than the upper, erect, not seiTnted. 



37. Isistins, p. 429. 



Fam. 8. RHINID^. 

 No anal fin. Pectorals deeply notched in front at the root. 



Mouth anterior 38. Ehina, p. 430. 



Fam. 9. PRISTIOPHORID.^. 

 Snout much produced, with lateral teeth, saw-like. 



Two barbels at the lower side of the saw. 39. rrisfiophortis, p. -^31. 



