CLASS V. PISCES: OEDER 1. SELACHIA. 
425 
1SS SHAKE. 
and sometimes marked with scattered spines or minute grains over the whole body. The 
branchiae are distinguished from those of other fishes by their structure, being arranged so as to 
allow the water used in respiration to pass off through separate external apertures. Most of 
the species produce living young, which are developed in an enlarged portion of the oviduct. 
All are generally of large size, and are inhabitants of the sea, though several species frequent 
the estuaries formed by large rivers. We shall notice them under the heads of Chimceridce, 
Squalidce, and Raiidoe, 
THE CHIM^RID^. 
Genus CHIMERA : Chimcera. — These animals have some resemblance to the sturgeons ; they 
have two dorsal fins, the anterior one being situated over the two powerful pectoral fins ; the anal 
fin is long and narrow, and the tail 
heterocercal. The best known spe- 
cies is the Northern Chimera or 
Sea-Cat, C. monstrosa, sometimes 
called ICinff of the Herrings. It is 
three to four feet long, of a silvery 
color, spotted with brown; feeds 
on herrings, the shoals of which it 
follows, and also on other fish, 
medusae, and Crustacea. It is found in the European seas, and occasionally on the British coast. 
^ Vol. IL— 54 
