xvi Introduction. 



Of the bony fishes the Acanthopterygii, or fishes with hard spiny fins, 

 are divided into fifteen families, the principal of which are the perch 

 family, the mailed cheek fishes, including the gurnards, the flying fish 

 of the Mediterranean, and the sticklebacks, or jack banticles; the 

 mackerel family, including the tunny, bonito, and sword-fish; the 

 pilot-fish, the dolphin of the Mediterranean, so celebrated for the 

 beauty of its dying tints, and the John Dory. Among the Malacop- 

 terygii abdominales, or soft-finned fishes, that have their ventral fins 

 suspended from the abdomen, the most interesting are the carp family, 

 the pike family, the flying-fish of the ocean, the salmon family, and 

 the herring family, including the sprat, pilchard, and anchovy. 



Tlie Malacopterygii sub-brachiati are soft-finned fishes, with the 

 ventral fins beneath the pectorals ; the principal of which are the cod 

 family, including the haddock, whiting, and ling ; the flat-fish family, 

 including soles, turbots, plaice, and flounders; and the suckers or 

 lump-fish. , 



The Malacopterygii apodes are confined to the eel family. 



Tke Lophobranchii include the pipe-fish, and other fishes of similar 

 form. 



The Plectognathi comprise the very singular forms of the balloon- 

 fish, the sun-fish, and other similar fishes. 



Tke Chondropteryg ii, or Cartilaginous fishes, are divided into three 

 orders, viz. the Sturiones, or sturgeon family; the Selachi, or sharks 

 and rays, including the torpedo ; and the Cyclostomi, or lamprey family. 

 The last two orders were included by Cuvier in a single one. 



THE MOLLUSCOUS ANIMALS 



Have no bones except their shells. Their sense of feeling appears to 

 be very acute, but the organs for the other senses are either wanting or 

 very imperfect. The blood is cold and white, and the heart often con- 

 sists of only one ventricle; a few of them have imperfect lungs, but 

 the greater number breathe through gills. They have all the power of 

 remaining a long time in a state of rest, and their movements are 

 either slow or violently laborious. Some of them appear incapable of 

 locomotion. They produce their young from eggs, but some lay their 

 eggs on a part of their own body, where the young are hatched. The 

 following are Cuvier's six classes: 



1. Cephalopoda, or Head-footed Mollusca. These animals are furnished 



with long fleshy arms or feet, proceeding from the head, which 

 is not distinct from the body, and on which they crawl. There 

 is only one order, which includes the cuttle-fish, nautilus, and 

 belemnites. 



2. Pteropoda, or Wing-footed Mollusca. These animals have two 



membranous feet or arms, like wings, proceeding from the 

 neck. There is only one order, which contains six genera, the 

 best known of which is the Hyalaea, the shell of which is com- 

 monly called Venus's chariot. 



3. Gasteropoda, or Body-footed Mollusca. All these animals crawl with 



the flat part of the body, which acts as a kind of sucker. There 

 are nine orders in Cuvier's system. The common snail will give 

 an idea of the habits 01' the class. 



