18 CONTRIBUTION& TO NORTH AMERICAN ICHTHYOLOGY IV. 



of the mouth, each being provided with a free cyUndrical cirrus; an 

 ujjper and lower lij), the latter not extending across the symphysis; 

 lomth and fifth gill-oi)euiiigs close together; eyes very small. The 

 backward i^osition of the lirst dorsal distinguishes this family from all 

 others in our waters. Genera two ; species about four ; large sharks of 

 the Avarm seas. {Hcyllndce pt. Giinther, viii, 407-409.) 



* Teeth ill both jaws in many scries, each with a strong median cnsp, and one or •(rwo 

 smaller cnsps on each side GlNGLYMOi:'TOMA, 1 i. 



13.— OINGLYMOSTOMA Miiller & Heule, 1837. 

 (Miiller & Heule, VViegmann's Arch. 1837, p. — : type Squahis cirratutf GmeUn.) 



The characters of this genus are those of the family above given, v-ith 

 the addition of the following, which distinguish Ginglymostoma from 

 Nebrius: teeth of both jaws in many series, each with a strong median 

 cusj), and one or two smaller cnsps on each side. (^'ty^-AD/zoc, a hinge or 

 hingo-hke joint; fTza/j.a, mouth.) 



1§. Cr. 4>ifi'r£ltllim (Giuel.) ^1. »S: H.—Xurse Shark. 



Uniform brownish ; young specimens with small, scattered, round 

 black si)ots; nasal cirrus reaching the lower lij); angles of the fins 

 obtusely rounded ; caudal fin forming nearly one-third of the total 

 length. L. to 10 feet. {Giinther.) 



A large shark of the warmer parts of the Atlantic, abundant in the 

 Gult of Mexico and the West Indies, and occasionally taken on our 

 South Atlantic coast. 



(iSgwo^/zs c(/-)Y(fH? Gmeliu's Linuppufi, i, 1492; Miiller & Henle, 23 ; Giinther, ^'iii, 408.) 



Super-family GALEORHINOIDEA. 



{The Galeorhinoid Sharl's.) 



Family VII.— GALEORHINID^ 



(The True Sharhs.) 



Sharks with two dorsals and an anal fin ; no sjnnes ; pectorals mod- 

 erate; caudal fin not greatly elongated, not lunate, moderately bent 

 upwards, notched toward its end, and with the basal nuich less devel- 

 oped than the up])er: caudal peduncle not keeled; posterior gill-opening 

 above the base of the pectoral fin; eyes with nictitating membranes; 

 head not hammer-shaped, the snout being longitudinally ])roduced as 

 usual among sharks. A large family of twenty or more genera and about 



