264 THE CANADIAN NATURALIST. [Aug. 



Genus Isuropsis Gill. 



Teeth nail-shaped, long, prismatic and acute. Dorsal nearly 

 midways between pectorals and ventrals. 



Isuropsis glaums Gill ex M. & H. Porbeagle. (Fortin.) 

 Lamna punctata, Storer, Dekay. 



Cetorhinin^e Gill. 



Branchial apertures extremely large. Teeth minute. 



Genus Cetorhinus Blainv. 



Cetorliinus maximus Gray ex Linn. B asking-shark. (Perley.) 

 Selachus maximus, Dekay. 



ALOPECIDJE Owen. 

 Genus Alopias Raf. 



Alopias vulpes Bon. ex Linn. Thresher-shark. (Perley.) 

 Carcharias vulpes, Dekay. 



GALEORHININID^E Gill. 

 Galeorhinin^e Gill. 

 Teeth compressed, trenchant, entire or crenulated. 



Genus Scoliodon Mull. & Henle. 

 Teeth with smooth edges, and with point directed toYards the 

 corners of the mouth. 

 * Scoliodon terrce-novce Gill ex Rich. 



Squalis (carcharias) terrae-no^ee, Rich., F. B. A., Fishes, 289. 



SPINACID^E (Owen). 

 Genus Squalus (Linn.) Raf. 

 Teeth of jaws similar, subquadrate, with a nearly horizontal 

 cutting-edge. 



Squalus Americanus Gill ex St. Dog-fish. (Perlep.) 

 Spinax acanthias ? Dekay. 



SCYMNID^E (Owen). 



Genus Somniosus Les. 



Teeth above narrow, triangular; below subquadrate, with a 

 nearly horizontal cutting-edge. 

 Somniosus microcephalus (Gray). 

 Scymnus brevipinna, Dekay. 



