96 TELEOSTEI : HEMIBRANCHII. — XVIII 
sal nor ventral fins ; caudal small or wanting ; anal minute, of 1 or 
2 rays; tail long. Male fishes with an egg-pouch, usually placed 
on under side of tail and formed of two folds of skin which meet on 
the median line. The eggs are received from the female into this 
pouch, and retained for some time after hatching, when the pouch 
opens and the young, then } to } inch long, escape. Genera about 
14; species 150, in all warm seas. (ovv, together; yvd6os, jaw.) 
a, Axis of head in a line with axis of body. (Syngnathine.) 
6. Humeral bones united below; C. present; P. well developed; D. oppo- 
site vent; shields not spinous. . . . . . . . SipHosroma, 105. 
aa. Axis of head forming an angle with axis of body; the head and neck 
horse-shaped, or like that of a “Knight” at chess. (Hippocampine.) 
c, Body compressed ; occiput with a narrow, bony crest, surmounted 
by a star-shaped coronet ; shields tubercular or spinous ; egg-sac 
in male at base of tail, which is prehensile and without fin. 
Hippocampus, 106. 
105. SIPHOSTOMA Rafinesque. Prre-FIsHEs. (cidav, tube; 
orépza, mouth.) 
235. S. fuscum (Storer). Common Pire-risa. Top of head 
slightly keeled; D. covering 4 body rings and 5 behind vent; rings 
18 to 20 -++ 36 to 40; dorsal rays 36 to 40; snout moderate. Head 
9; L. 7. Olivaceous, sides mottled. Newfoundland to Va., com- 
mon. Numerous other species occur 8. (Lat., dusky.) 
106. HIPPOCAMPUS Rafinesque. Sea Horszs. 
(These small fishes inhabit grassy bays and often the open sea 
in warm regions. They are wont to twist the very prehensile tail 
around pieces of floating sea-weed or eel-grass. They are thus often 
drifted to great distances in the sea. The species are very simi- 
lar to each other, and not easily distinguished.) (Ancient name 
from immos, horse, and xdyzos, a wriggling creature.) 
236. H. hudsonius DeKay. Sea Horse. Dusky, unspotted, 
but with grayish blotches, edged with blackish; D. with dark band; 
snout 14 in head; spines on head weak, with cirri; spines all blunt- 
ish. D. 19, on 34 of the 11 body rings. L.6. Cape Cod to Fla., 
not common. Several other species occur S. 
Orver XVII HEMIBRANCHIL (Tue Hatr-eiiiep 
FIsHEs.) 
Gills normal, but the branchihyals and pharyngeals reduced in 
number; V. more or less abdominal. A small group of 5 or 6 fam- 
ilies. intermediate between the Lophobranchii and the true Acan- 
thopteri. (qys-, half; Bpdyxea, gills.) 
