CRUSTACEA. 35 



Besides the tentacula, the Cuttle fish is furnished with 

 a pair of arms, with the ends expanded and also fur- 

 nished with suckers. These long members are employ- 

 ed as cables, and the suckers as anchors, by which, these 

 animals fix themselves firmly to rocks during violent 

 agitations of the sea, and without which they would un- 

 doubtedly sometimes be dashed to death against the 

 rocky shores. These long arms are not employed by 

 the animal in swimming, the short ones being used as 

 oars for the purpose of impelling this singular creature, 

 not forward but backward, for in this manner do all the 

 Cuttle fish tribe swim. Some of them are 15 or 20 

 feet long. 



ARTICULATA. 



The animals now to be noticed are articulated, or are 

 provided with joints, by means of which their hard and 

 inflexible parts become the instruments of motion. 

 Hence this division includes animals having joints, wheth- 

 er large or small, and by which they are at once distin- 

 guished from the mollusca, where nothing analagous to 

 articulation exists. This division contains a vast assem- 

 blage of living beings, including the Insects, Fishes, and 

 Quadrupeds. The limits of this work will however al- 

 low an account of the physiology of only a few of the 

 most curious and important. 



CRUSTACEA. 



The Crustacea are animals encased in a compact, 

 crusty frame-work, composed chiefly of carbonate of 

 lime, as the Lobster, and Crab. 



The joints of Crustaceous animals are constructed in 

 the most admirable manner, by which in most cases 

 every part of the limb can be moved in all directions. 

 They have either three or four pairs of legs, each of 

 which is divided into five pieces, by as many joints. On 

 each side of the head there is a long, and often very 



Why are certain animals denominated articulata? What races of 

 animals are articulated ? What are the Crustacea 1 What parts of these 

 animals are called antennae 7 



