INTRODUCTION. 15 



long time. They are extremely tenacious of life, and can repair certain parts of their bodies which have been 

 lost. They are also able to endure hunger, sometimes even for months, without injury. 

 This class was divided into two orders. 



I. Reptiles. — Having four legs, and walking with a crawling pace, as the tortoises, toads, aud lizards. 



II. Serpents.— Having no legs, but crawling on the body. 



Class IV. — Fishes. 



This class included inhabitants of the water, which move by certain organs called fins. Those situated on 

 the back are called dorsal fins ; those on the sides, behind the gills, pectoral fins ; those below the body, near 

 the head, are ventral ; those behind the vent are anal ; and that which forms the tail is called the caudal fin. 



The fishes were divided into six orders. 



I. Apodal. — Having bony gills ; and no ventral fins, as the eel. 



II. Jugular.— Having bony gills ; and the ventral fins situated in front of the pectoral fins, as the cod, had- 



dock, and whiting. 



III. Thoracic— Having bony gills ; and the ventral fins situated directly under the pectoral fins, as the perch 



and mackerel. 



IV. Abdominal. — Having bony gills ; and the ventral fins on the lower part of the body below the pectoral 



fins, as the salmon, herring, and carp. 



V. Branch iostegous. — Having gills destitute of bony rays. 



VI. Chondropterygeous. — Having cartilaginous fins, as the sturgeons, sharks, and skate. 



Class V. — Insects. 



This class comprised the Insects ; and the branch of zoology which treats of them is called Entomology. 

 It was divided into seven orders. 



I. Coleopterous. — Having elytra, or crustaceous cases covering the wings ; and which, when closed, form a 



longitudinal division along the middle of the back, as the cockchafer. 



II. Hemipterous. — Having four wings, the upper ones partly crustaceous and partly membraneous ; not di- 



vided straight down the middle of the back, but crossed, or incumbent on each other, as the cock- 

 roach. 



III. Lepidopterous. — Having four wings covered with fine scales almost like powder, as the butterflies and 



moths. 



IV. Neuropterous. — Having four membraneous and semi-transparent wings, veined like net-work ; and the 



tail without a sting, as the dragon-fly and ephemera. 



V. Hymenopterous.— Having four membraneous and semi-transparent wings, veined like net-work ; and the 



tail armed with a sting, as the wasp and bee. 



VI. Dipterous. — Having only two wings, as the common house-flies. 



VII. Apterous.— Having no wings, as the spiders. 



Class VI. — Vermes, or Worms. 

 These are slow of motion, and have soft and fleshy bodies. Some of them have hard internal parts, and 

 others have crustaceous coverings. 



I. Intestinal.— Are simple and naked, without limbs ; some of them live within other animals, as the 



ascarides and tape-worms ; others in water, as the leeches ; and a. few in the earth, as the earth- 

 worm. 



II. Molluscous.— Are simple animals, without shells, and furnished with limbs, as the cuttle-fish, medusa-, 



star-fish, and sea-urchin. 



III. Testaceous.— Are animals similar to the last, but covered with shells, as oysters, cockles, snails, and 



limpets. 



IV. Zoophytes.— Are composite animals, and appear to hold a rank between animals and vegetables ; though 



they are in fact true animals, and possess sensation and voluntary motion. In many instances a great 

 number of them inhabit the same stone, but some are soft, naked, and separate. The coral, sponge, 

 and polypes are instances of this order. 



V. Animalcules.— Are destitute of tentacula or feelers, and are generally so minute as to be invisible to the 



naked eye. They are chiefly found in different infusions of animal and vegetable substances. 



This classification continued to be the leading one among- scientific men,, till the publication of 

 'the Animal Kingdom of George Cuvier, in 1816. This admirable work, being founded upon a 



profound study of the structure of animals by means of dissection, was generally adopted; and 

 ; though portions of it have been modified by the researches of eminent naturalists in particular 

 [branches of zoological science, and hence new systems of classification have been proposed and 

 ' adopted, it still remains as -the basis of all those which have acquired reputation with the 



learned world. This classification is as follows : 



