14 CONTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY — IV. 
but little arclied ; a long, deep, straight, oblique groove on each side of 
it ; spiracles present. (The absence of dorsal spines chiefly cbstingmshes 
this family from Spinacidcc.) 
Genera six ; species six or more, mostly of the Atlantic. (Giinther, 
Spinacldcc, pt. viii, 425-429.) 
^ First dorsal opposite ventrals ; teetli equal in both jaws, very oblique ; skin rough 
with tubercles and prickles Echixorhinus, 8. 
** First dorsal much iu advance of ventrals; the dorsals .about equal; upper teeth 
narrow ; lower quadrate, with a horizont.al edge ending in a point directed 
outwards SoMNiosus, 9. 
§.— ECIIII^iOISHIJ^US Blainville, 1816. 
Sjnnous Sharl's. 
(Goniodus Agassiz.) 
(Blainville, 1816; type Squahis spinosus Gmelin.) 
Two very small dorsal fins without spine, the first opposite the ven- 
trals I 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 point being 
turned outwards; several strong denticulations on each side of the 
j^rincipal point, l^o nictitating membrane. Spiracles small ; gill-open- 
ings of moderate width. A single species of the East Atlantic, straying 
to our coast. a hedgehog, or sea-urchin ; pc>7j, shark.) 
13. E. spimostis (Gmel.) Blainv. — Spinovs Shark; BoucU. 
“ Spiracles behind the eye, behind the vertical from the angle of the 
mouth. Teeth Dorsal fins close together. Each tubercle with a 
small si)ine 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. 
(Squahts sjnnosus Gmelin Linn. 1, 1500; Giintber, viii, 428.) 
9.— SOI?Il\IOSES Le Siieur, 1818. 
Sleeper Sharhs. 
{Lcemarqus Miiller & Henle.) 
(Lc Sueur, Journ. Ac. Nat. Sci. Phila. 1818, i, 222; type, Somniosus hrcvipimia Le 
Suenr = Squahis microcephahis Block.) 
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 uxiper jaw small, narrow, conical ; lower 
