116 ZOOLOGY. 



the sixth. These Crustacea, although they walk well, must be regarded as 

 chiefly swimmers, shooting backwards through the water by the action of 

 the abdomen and caudal fin, 



Fam. 1. ScyllaridcG {cuirasses, M. Edwards). In the genus PaUmirus 

 pl. 7S, Jig. 11) the body has much the shape of that of a lobster, but is 

 more cylindrical, and none of the feet are cheliform, although the anterior 

 ones are rather more robust than the others. The caraj^ace is cirmed 

 anteriorly with two large spines ; the external antennae are very long, with 

 the base spiny ; the basal segment of the abdomen is without false feet, 

 although the four following have them. The species are of a large size ; 

 they have a very hard shell, and they live upon rocky coasts. The European 

 species, P. milgaris, attains a length of fifty centimetres, and a weight of 

 eight kilograms. It is the Icarabos of Aristotle, and the locusta of Suetonius 

 and Belon. The various species are more or less spinous. Scyllarus [pi. 

 78, jig. 12) is remarkable for having the peduncle of the exterior antennae 

 much dilated laterally, and more or less dentated, the terminal filaments being 

 absent. The sub-flimilies are : GalatJieince, Enjoninm.^ Scyllari7ice, and 

 Palinurinm. 



Fam. 2. Astacidce. This family includes the genus Astaciis (lobster) and 

 Potcmiobia,, the analogous fresh water form known under the English names 

 of crawfish, crayfish, crevish, or ere vis, the three last of which agree in the 

 first syllable. The latter are caught in Euroj)e for food, by placing decaying 

 meat in nets or bunches of brushwood, from which they cannot readily 

 escape. They are also caught by a bait at the end of a stick, which they 

 will not leave if it is withdrawn slowly, until a net can be passed nnder 

 them. They are said to live twenty years, and to grow during this period. 

 The genus is well represented in the United States. Callianassa {pi. 78, 

 jig. 14). C. major., of Say, is four inches and a half long, and was found 

 by this author " by digging in the sand of the bay shore of the river St. 

 John, in East Florida, about eighteen inches below the surface, near low- 

 water mark ; it had formed a tubular domicil, which penetrated the sand in 

 a perpendicular direction to a considerable depth ; the sides were of a more 

 compact consistence than the surrounding sand, projecting above the surface 

 half an inch or more, resembling a small chimney, and rather suddenly 

 contracted at the top into a small orifice." The second family, fouisseuTS of 

 Milne Edwards, is included in the Astacidce by Latreille. The sub-families 

 are : OlaiiGothoincB., Callianidinm, and Astacince. 



Famj. 3. Palmmonidce. Palcemo7i, which is much used for food, inhabits 

 sandy bottoms near the coasts, or the mouths of rivers, and like the lobsters, 

 boiling turns them red. Stenojms {pi. 78, jig. 13, exhibiting the false feet 

 under the abdomen). The sub-families are : Crangoninm., Alpheinm, 

 Palmmoninm, and Penmince. 



Fam. 4. Mysisidm''^ Some authors place this family with the Stomatopoda. 

 It includes two sub-families : Mysisinm and Leuciferinm. 



* Under a different form this name might be supposed to be derived from Mysia or Mysidia, 

 instead of Mysis. 

 320 



