166 BACKBONED ANIMALS. 
Notr.—The eggs of the Chimera are deposited in thick, leathery 
cases, and those of Calorhynchus are remarkable for their mimicry or 
protective resemblance, resembling the leaf of the fucus or sea-weed to 
which they are attached. They form a long, depressed ellipse, with a 
plicated and fringed margin, and, swaying in the current, their true 
nature would never be suspected, 
Sub-Class II. BriGHT-scaLeED Fisues (Gaxoide?). 
General Characteristics —The Ganoids have hard, glis- 
tening scales, cartilaginous or ossified skeletons, and one 
pair of gill-openings, protected by opercular bones. 
Fic, 204.—Sharp-nosed sturgeon (4. oxyrhynchus). 
Order I. Chondroganoidei. The Sturgeons (4ci- 
penseride).—The sturgeons (Fig. 204) have cartilaginous 
skeletons, the skin being armed with bony bucklers or 
plates, arranged in longitudinal rows. The mouth is 
toothless and under the snout, 
and is adapted for sucking in 
soft food (Fig. 205). The sharp- 
nosed sturgeon attains a length 
of eight feet. It breeds, as do 
Fic. 205.—The sturgeon’s the entire family, in fresh water, 
head seen from below, Peas ia 
showing the tube-like the female depositing millions of 
mouth and the fourbar- eggs. The shovel-nosed stur- 
bels or feelers, geon and the curious spoonbill 
(Polyodon folium) are found in 
the Mississippi. Glue, cement, court-plaster, isinglass, 
etc., are made from the air-bladders of sturgeons. 
Note.—The Acipenser huso attains a length of twenty-five feet. 
The fisheries at Ruibinsk, on the Volga, Russia, give employment, ac- 
cording to Duncan, to one hundred thousand persons, and the fish have 
