(JOG 



ARTICULATA. 



within H cavity on each side of the ccplialothorax. The trae thoracic legs are almost always ten 



in number — whence the name of the 

 order. It includes an immense number 

 of species, generally of consideraVjle size 

 when compared with the other Crustacea. 

 AVe shall notice them under three sub- 

 orders, the Macrura, Anomura, and Bra- 

 chyura. 



THE MACRURA. 



This term, from the Greek makros, long, 

 and oura, a tail, embraces those species 

 which are generally called the Long- 

 tailed Decapod Crustacea. 



THE CRAXGONID^. 



This family includes the well-known 

 Shrimps and Prawns. They are distin- 

 guished by the possession of a large oval 

 or triangular appendage which covers the 

 base of the first joint of the outer an- 

 tenna?. In their general appearance they 

 all present a considerable resemblance to 

 the Common European Shrimp, Crangon 

 vulgaris. They inhabit salt water, and 

 generally occur in large numbers, found 

 together on sandy coasts ; and in spite 

 of their small size, they are everywhere 

 in great request as articles of food. The 

 common shrimp of Europe is about two 

 inches long ; the Common European 

 Prawn, Palemon serratus, is three to 

 four inches long. The American Bait- 

 Shrimp, Crangon septemspinosus, and the 

 American Prawn, Palemon vulgaris, are 

 common on our coasts. 



THE ASTACID^. 



To this family belongs the Common 

 Lobster, distinguished from the preceding 

 by the small size of the appendage at the base of the outer antennae, besides many other differ- 

 ences in form and structure. The anterior pair of feet is always much larger than the others, and 

 armed with powerful nippers. Some of these animals live in fresh water. These are of a smaller 

 size than the marine species, but are also eaten in great numbers by the inhabitants of the neighbor- 

 hoods where they occur. Lobsters change their shell annually ; before casting the old shell they are 

 sickly and grow thin, and thus, though with great effort and apparent suffering, the old covering 

 is cast off, and the new one is speedily formed by secretion. Sometimes lobsters throw off" their 

 claws in consequence of fright, and often they will hold on to an object till the claws are torn 

 off. To some extent these lost parts are reproduced. They are very active in the water, and 

 can spring to a considerable distance ; they feed chiefly at night. They are voracious, and eat 

 any animal matter that comes in their way. Immense numbers of the European Lobster, -4s- 

 tacns marinus, are taken, hut the means of increase are abundant, twelve thousand four hundred 

 and forty-four eggs having been found under the tail of a single female. The Common American 



THE SHRIUP. 



