FISHES. 377 



The observations of Sir E. HOME, indicate this species to 

 be ovoviviparous *. 



9- CESTRACTON. (CuviER.) A spine in front of each of 

 the dorsal fins. C. Phillippi. 



(BB.) Teeth blunt and closely set. 



10. MUSTELUS. Dorsal fins unarmed. M. vulgaris. 

 b. With one anal fin. 



11. NOTIDANUS. Resembling the genus Galeus. N. 

 griseus. 



(II.) Destitute of an anal fin. Two of the genera have 

 the dorsal fins armed with spines, the third is unarmed. 



12. SPINAX. Teeth small, with a cutting edge. The 

 dorsal spines in front of the fins. S. acanthias. This spe- 

 cies is ovoviviparous f. 



13. CENTRINA. Under teeth edged, upper ones point- 

 ed. The dorsal spines contained in the fins. C. vulgaris. 

 BLOCK, Ichthyologie, t. 115. 



14. SCYMNUS. This includes the Squcdus Americamis 

 of GMELIN. 



(B.) Destitute of temporal orifices. 



15. CAIICHARIAS. Snout conical. This genus includes 

 the following British species. C. vulgaris. White Shark, 

 C. vulpis, Thresher. C. glaucus, Blue Shark, and C. cor- 

 nubicus, Probeagle Shark. 



16. ZYGANA. Balance Fish. Snout truncated, and 

 spread out on each side like the head of a hammer. The 

 eyes are placed terminally on these productions. Z. Blochil 

 BLOCH, tab. 117. 



A. Pectoral fins coalescing with the snout. The body 

 is depressed. The eyes and temporal orifices are on the 

 dorsal surface of the snout; the mouth, nostrils, and gill- 

 openings on its ventral surface. 



^ 



* Phil. Trans. 1810, p. 211. f Ibid. 



