62 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 



"31 (?0.— SiESANCMtJS* Rafiuesque. 



" {Notklanns Cuvier.) 



"(Rafinesque, Caratteri tli Alcuui Nuovi Geueri, etc. 1810, 14: type Squalus griseus 

 LinnfEiis. ) 



" Brancliial apertures six on each side; otherwise essentially as in Hep- 

 trancMas. Two species known, (ef, six; ayxw:, bend or sinus; for gill- 

 opening.) 

 *'41 (/')• BI. coriaius Jordan & Gilbert. — Shovel-nosed Sltarlc. 



"Color almost black, unspotted; a grayish lateral streak. Head 

 large, broad, depressed and blunt. ]Slo median tooth in upper jaw. 

 About six pointed teeth in front of upper jaw, all entire and without 

 basal cusps. Next three teeth with entire edges and a single cusp on 

 the outer margin. Eemainiug teeth of upper jaw serrate on the inner 

 margin, and with two or more basal cusps on the outer. Median cusj) 

 of lower jaw very small. Other teeth with six cusps, the first the 

 largest, the others regularly smaller, the inner edge in the adults ser- 

 rated. Tail long, twice as long as head, a little less than one-third the 

 total length. Scales on upper edge of tail enlarged. Monterey to Pu- 

 get's Souud. 



" (Jordan & Gilbert, Proc. U. S. Nat. Mas. 1880, 352.) 



"32. HEPTKANCHIAS Rafinesque. 

 " (Notorhynchus Ayres.) 



"(Rafiuesque, Caratteri di Alcuui Nuovi Generi, etc. 1810, 13: tyi^e Squalus cinereiis 

 Gmelin.) 



" Gill-openings seven on each side. Three species known, (i-rd, seven ; 

 I3pdyyja, gills. The change of this name to " Heptanchus^^ is hardly justi- 

 fiable.) 

 "42. M. iMactilattMS (Ayres) Girard. 



" Sandy gray, with some round black spots, larger than the pupil, 

 rather sf)arsely placed. Head rather depressed; the snout broad, 

 rounded ; the nostrils near its tip ; spiracles large, nearer the gill-open- 

 ing than the eye ; a long furrow at the angle of the mouth. No median 



* The necessities of nomenclature often require the substitution for the name of 

 the typical genus of a family of some less familiar but earlier name, as Hexanehns 

 for Notidanus, Carcharias for Odoniaspis, Dasyhatus for Trygon, etc. It is i^robably un- 

 necessary to change well-known family names to accord with these changes. Among 

 our sharks it is perhaps better to retain the old family names Odoniaspididce, NoUdnni- 

 dce, Cestraciontidce, instead of Carehariida;, Hexanchidcv, and Heterodontidce, as given in 

 the text. The name Carehariidw, used by various authors for the Galeorrliinidw, is in- 

 eligible, because the name Carcharias rightfully belongs to a genus of another family. 



