58 STURGEONS. CHIMJERID2E. SHARKS, ETC. 



which fall into the Black and Caspian seas. The common 

 Sturgeon attains the length of six feet ; but the great Sturgeon 

 has been found twelve or even fifteen feet in length, and weighing 

 from 1200 to 3000 Ibs. The flesh of the former is very palatable 

 and wholesome, resembling veal in its character ; that of the 

 latter, however, is not esteemed. The Sterlet is a smaller 

 species, about two feet long ; which is found in the Russian 

 rivers, and is considered a great delicacy. All the species are 

 valued on account of the excellent Isinglass which is yielded by 

 their air-bladders ; and their roe is salted and prepared by the 

 Russians, forming a dish termed caviare. More than 400,000 Ibs. 

 of this have been prepared in the Caspian fishery, in a single 

 year. The CHIM^ERID^E have the gills not entirely free at their 

 extremities, but partly attached, as in the Sharks ; and although 

 there is externally but a single gill-opening, yet internally there 

 are five separate passages, terminating in the common aperture. 

 They lay large, flattened, eggs, included in a sort of leathery 

 covering; in which respect, also, they resemble the Sharks. 

 The commonest species is known under the name of the " King 

 of the Herrings." 



ORDER VIIL CHONDROPTERYGII BRANCHIIS 

 FIXIS. 



582. This order includes the two families of Sharks and 

 Rays ; which, though very different in external form, agree in 

 many points of internal structure, and particularly in having the 

 gills fixed at their extremities to the outer sides of the gill-cavity, 

 and in having a series of apertures, through which the water 

 passes out from each branchial arch. In these particulars they 

 correspond with the last order of the class, that of Cyclostome 

 Fishes ; but they differ from them in having a much more per- 

 fect skeleton, and in having both pectoral and ventral fins. The 

 differences between the two families of SQUALID^:, or the Shark 

 tribe, and RAID^E, or the Ray tribe, chiefly consist in their 

 external form ; the body in the former being elongated, and the 



