AMPHIPODA. 



CRUSTACEA. 333 



segments on each side terminating in a long, curved spine. I 

 have found it, rather abundantly, in fishes. 



Genus MYSIS, Latr. 



M. spiNULo'sus. Tail terminated by two short spines and tico 

 longer^ ciliated plates folding inwards. 



Cancer pedatus, Fabr. ; Fauna Grard. 243. 



Mysis saltatorius, Lam. ; An. sans Vert., v. 34G. 



M3'sis spinulosus, Desm. ; Consid., 242. 



IVlysis Fabn'cii, Leach; Griffith's Cuv., xiii. (Crust.) pi. 17, f. 4. 



Mysis Leachii, Thompson ; Zool. Researches, i. 27. 



This curious little animal may be found abundantly, in the midst 

 of winter, in still water along the margins of bays. Its head seems 

 to have a long pair of beautifully fringed shears attached in front ; 

 each joint is marked upon the back with a black star ; and be- 

 tween the legs of the females is seen a large sac, containing eggs. 

 Two of the antennae are very long ; and the whole is quite trans- 

 parent. It is about an inch in length. 



Genus NEBALIA, Leach. 



A single species has been observed, but the species has not 

 been satisfactorily made out. It is small, the body covered by a 

 single piece like a cuirass, the tail suddenly narrowing, long, and 

 terminating in two bristles. Multitudes are sometimes found in 

 the stomach of a single fish. 



AMPHIPODA. 



The Amphipoda are small Crustacea, inhabiting both fresh and 

 salt water, and some of them are well known to every one who is 

 familiar with the sea-shore, under the name of Sand-Jleas, Beach- 

 fleas, &c. They are capable of swimming and leaping, but not 

 of walking. Their feet are short and unequal, and their body is 

 usually so arched as to render it impossible to maintain themselves 



