Fishes of the Western North Atlantic 265 



lib. Second dorsal less than ^2 as long at base as ist and much smaller 

 in area, its posterior margin only weakly concave, or nearly 

 straight. 



1 2a. Bases of upper teeth, as well as of lowers, smooth-edged. 

 13a. Teeth slender, symmetrical, erect in both jaws; long- 

 est gill opening nearly or quite V2 as long as base of 

 1st dorsal.' Aprionodon Gill, 1861, p. 303. 



13b. Teeth in sides of jaws oblique, their outer edges 

 notched; longest gill opening only about Y^ as long as 

 base of ist dorsal. 

 14a. Teeth with swollen rounded bases. 



Protozygaena Whitley, 1 940. 



Australia. 



14b. Teeth not swollen at base. 



ScoUodon Muller and Henle, 1837, p. 292. 

 1 2b. Bases of upper teeth with serrate or denticulate edges. 



Hypo-prion Muller and Henle, 1841, p. 315. 

 lOb. Margins of cusps of upper teeth regularly serrate; lowers either ser- 

 rate or smooth. Carcharhinus Blainville, 18 16, p. 320. 



Genus Galeocerdo Muller and Henle, 1837 



Galeocerio Muller and Henle, Arch. Naturg., (3) i, 1837: 397; type species, Squalus arcticus Faber, 1829, 

 Iceland, equals Squalus cuvier Lesueur, 1 822, Australia. 



Generic Synonyms: 



Squalus (in part) Lesueur, J. Acad. nat. Sci. Philad., 2, 1822: 351; Faber, Fische Islands, 1829: 17; not 



Squalus Linnaeus, -1758. 

 GaUus L. Agassiz, Poiss. Foss., 5, 1835: pi. E, fig. 5, 6; Poiss. Foss., 5, 1838: 91 ; type species, G. cefedianus 



L. Agassiz, East Indies; not Galeus Rafinesque, 18 10. 

 Prionodon (subgenus in part) Bleeker, Verh. bata"ia. Genoot., 24, Plagiost., 1852: 37; for P. jasciatus, Java; 



not Prionodon Muller and Henle, 1 841. 

 Boreogaleus Gill, Ann. N. Y. Lye, 7, 1 861 : 402, 41 1 ; type species, Squalus arcticus Faber, 1829. 

 /f^ray Townsend, Bull. N. Y. zool. Soc, 5^ (6), 1931: 168, photograph of Galeocerdo mislabelled "Isurus 



tigrinus," evidently by mistake. 



Generic Characters. Anal only a little longer at base than 2nd dorsal; spiracles pres- 

 ent, small; 2nd dorsal originates over or a little in front of origin of anal; 2nd dorsal only 

 a little more than V2 as long at base as ist dorsal, and considerably less than Yo as large in 

 area; midpoint of base of ist dorsal only about Yz as far from axil of pectoral as from 

 origin of pelvics; caudal peduncle with a low longitudinal dermal ridge on each side; 



5. The gill openings are as long as this in the most recent illustration of A. brevipinna Muller and Henle, 1841 

 (Whitley, Fish. Aust., /, 1940: 108, as "Longmania brevi-pinna"), although pictured as considerably shorter in 

 the original illustration of that species (Muller and Henle, Plagiost., 1 84 1 : pi. 9) . 



