356 SELACHOIDEI. 



Upper teeth erect, tricuspid, the lower oblique. 



31. %'«rtx, p. 424. 

 Teeth equal in both jaws, very small, tricuspid. 



32. CentroscyUium, p. 425. 



8. Dorsal Jins toithout spine ; the Jirst conspicuotcsly in advance of the 

 v^ttrals. 



Dorsal fins equally short. Lower teeth erect, triangular. 



?>3. Scy7mius, p. 42.5. 

 Dorsal fins equally short. Lower teeth oblique, truncate. 



34. Lcemargus, p. 420. 

 The second dorsal much longer than the first. 



3.5. Eiqwotomiaiis, p. 427. 



4. Dorsal Jins without spine ; the Jirst opposite to the ventrals. 



Teeth equal in both jaws, large, Aei*y oblique, denticulated. 



36. Echinorhinus, p. 42R. 

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



37. Isistitis, p. 429. 



Fam. 8. RHINID^. 

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



Mouth anterior 38. Fhna, p. 4.30. 



Fam. 9. PRISTIOPHORID.^. 

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

 Two barbels at the lower side of the saw. 39. Pristiophorus, p. 431. 



