GO. CENTRISCID^. 
387 
terior margin of orbit; tail longer than head and body together; snont 
ra ther shorter than opercle ; supraorbital spine nearly half diameter of 
eye; coronet well develoiied, with five spines. D. 19; A. 4. Rings 10 
4- 38. San Diego, Cal , and southward ; reaching a length of nearly a 
foot. 
(Girard, U. S. Pac. R. R. Sirrv. Fislies, 1S58, 34-2.) 
Ordep. S-HEMIBRANCHIT. 
{The Hcmihranchs.) 
Superior branchihyal and pharyngeal bones reduced in number ; in- 
ferior pharyngeals separated. Ventral fins abdominal or snbabdomiual. 
Month bounded above by premaxillaries only ; interclavicles developed. 
Xo pneumatic duct to the air-bladder. (Cope.) There are also several 
striking peculiarities in the structure of the shoulder girdle and the skull, 
by which these fishes differ from the Acanthopteri, with which group un- 
der one name or another they have usually been combined, {r^/i'., half; 
ISpdy/ca, gills.) 
ANALYSIS OF FAMILIES OF IIEMIBRANCHII. 
* Bones of head produced into a long tube, M'liicb bears the short jaws at its end. 
a. Body short, compressed, scaly ; no teeth ; si>inoiis dorsal present. 
Centriscid.e, CO. 
aa. Body elongate ; teeth present. 
J). Dorsal sxiines none ; a long caudal filament; no scales Fistulariiile, G1. 
ib. Dorsal sjiines jiresent, disconnected ; no caudal filament. 
c. Body covered with ctenoid scales Aulostomatid.e, 62. 
cc. Body scaleless, with bony shields Auloriiynciiid.e, 63. 
** Bones of head moderately xmodnced ; ventralsl, 1 ; dorsal x)receded by free spines; 
body scaleless, naked or mailed Gasterosteid^e, 64. 
Family LX.— CENTRISCIDiE. 
{The Snipe-Jishes.) 
Body compressed, oblong or elevated, covered with small rough scales; 
no lateral line ; some bony strips on the side of the back and on the 
margin of the thorax and abdomen, the former sometimes coutlueut into 
a shield. Bones of the skull much prolonged anteriorly, forming a long 
tube which bears the short jaws at the end ; no teeth. Gill-openings 
wide ; branchiostegals 4.* Two dorsal fins, the first of 4 to 7 spines, the 
second of which is very long and strong ; soft dorsal and anal moderate ; 
ventral fins small, abdominal, of 5 soft rays ; pectorals short ; caudal fin 
emarginate, its middle rays not produced. Air-bladder large; pseudo- 
