18 SELACHIL: SQUALI. — IV. 
Famity IX. CARCHARIIDA). (Tue Sanp Suarxs.) 
Body elongate, the snout sharp; mouth wide, the teeth large, 
long, narrow, entire, very sharp, most of the teeth with one or two 
small cusps at base; gill openings all in front of pectorals; dorsals 
small, similar to the anal; tail as in Galeorhinide ; no nictitating 
membrane; spiracles minute. One genus and 3 species; rather 
small sharks, of the Atlantic. 
13. CARCHARIAS Rafinesque. (Odontaspis Agassiz.) 
(xdpxapos, jagged.) 
a. First and fourth teeth of the upper jaw, and first tooth of the lower without 
basal cusps. (EZugomphodus Gill.) 
18, C. littoralis (Mitchill). Sanp SHarx. Pectoral short. 
Color gray. L. 6 feet. Cape Cod to S. C., rather common N, A 
voracious little shark. (Lat., of the shore.) 
Famity X. LAMNIDAS. (THE PorBEacues.) 
Body robust, contracted to a rather slender tail, which has a 
keel on each side ; caudal fin lunate, the lower lobe nearly as large 
as the upper, and not very different in form; teeth large; gill 
openings wide, all in front of pectorals; first dorsal and pectorals 
large; second dorsal and anal very small; a pit at root of caudal, 
spiracles obsolete. Large, voracious sharks of the warm seas. 
Genera 3, species about 6. 
u. Teeth slender, sharp, with entire edges; tail very slender. 
6. Teeth very slender, flexuous, without basalcusps . . . Isurus, 14. 
bb. Teeth broader, most of them with a small cusp on each side at base. 
Lamna, 15. 
aa. Teeth broad, compressed, triangular, distinctly serrate; tail rather stout. 
CaARCHARODON, 16. 
14. ISURUS Rafinesque. (cos, equal; ovpd, tail.) 
a. First dorsal entirely behind pectorals, nearly midway between base of P. 
and V. (Jsuropsis, Gill.) 
19. I. dekayi (Gill). Mackeren Suwarx. Color bluish. 
L. 15 feet. W.I., rarely N. (For James E. Dekay, author of the 
Fauna of New York.) 
15. LAMNA Cuvier. (Adpva, a kind of shark.) 
20. L. cornubica (Gmelin). PorBEAGLE. Mackere SHARK. 
First dorsal close behind pectorals; snout conical, sharp; back 
elevated ; third tooth on each side in upper jaw small. L. 8 feet. 
Warm seas, frequently N. to Cape Cod. (Hu.) (Lat., pertaining 
to Cornwall.) 
