14 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY — IV. 



bat little arched ; a long, deep, straight, oblique groove on each side of 

 it ; spiracles present. (The absence of dorsal spines chiefly distinguishes 

 this family from Spinacidte.) 



Genera six ; species six or more, mostly of the Atlantic. (Giinther, 

 Spinacidw, pt. viii, 425-429.) 



* First dorsal opposite ventrals; teeth equal in both jaws, very oblique ; skin rough 

 with tubercles and prickles ^, Echixorhinus, 8. 



** First dorsal much in advance of ventrals; the dorsals about equal; upper teeth 

 narrow ; lower quadrate, with a horizontal edge ending in a point directed 

 outwards , 4 SoMNiosus, 9, 



8.— ECIII«<©I£IIBIVUS BlainviUe, 1816. 



Spinous SJiarlcs. 



(Goniodus Agassiz.) 

 (BlainviUe, 1816; type Squalus spinosus Gmelin.) 



Two very small dorsal fins without spine, the firs4; opposite the ven- 

 trals; no anal fins; skin with scattered large round tubercles, sur- 

 mounted by prickles, like those on a bramble, and, like them, leaving a 

 scar when detached. Mouth crescent-shaped, a labial fold around the 

 angle of the mouth ; nostrils midway between the mouth and the end of 

 the snout. Teeth equal in both jaws, very oblique, the i)oint being 

 turned outwards; several strong denticulations on each side of the 

 principal point. Ko nictitating membrane. Spiracles small ; gill-open- 

 ings of moderate width. A single species of the East Atlantic, strajing 

 to our coast, {lyjvo'-, a hedgehog, or sea-urchin; pcvv], shark.) 

 13. E. spiBlOSUS (Gmel.) Blainv. — Spinous Shark; JBoucU. 



" Spiracles behind the eye, behind the vertical from the angle of the 

 mouth. Teeth l^f^- Dorsal fins close together. Each tubercle with a 

 small spine in the centre. Brownish violet, with or without dark spots" 

 {Giinther). A large shark of the coasts of Europe and Africa; a stray 

 individual lately taken on Cape Cod. 



(Squalus spinosus Gmelin Linn. 1, 1500; Giinther, viii, 428.) 

 9.— SOMIVIOSUS Le Sueur, 1818. 



Sleeper Sharlcs. 



(Laimargus Miiller Sz, Henle.) 



(Le Sueur, Journ. Ac. Nat. Sci. Phila. 1818, i, 222; type, Somniostis hrevipinna Le 

 ^nawr ^ Squalus microceplialus Bloch.) 



Body elongate; mouth transverse, little arched, with a deep straight 

 groove running backward from its angle ; nostrils near the extremity of 

 the snout ; jaws feeble ; teeth in upper jaw small, narrow, conical ; lower 



