AMPIilPODA. 11 



Group NOBMALIA. 



This group comprises the typical Amphipoda, and in- 

 cludes the whole of the order except those forms which 

 have some of the appendages absent, or have the first 

 joint of the legs absorbed into the body of the animal. 

 It is synonymous with the order of Amphipoda of 

 Latreille, Milne-Edwards, &c., and is separated into two 

 divisions namely, GAMMARINA and HYPERINA. 



Division GAMMARINA. 



Distinguished from the other division of the group by 

 the smallness of the eyes, the normal form of the antennae, 

 the size of the foot-jaws, and the largeness of the squa- 

 miform plates of the legs. This division corresponds 

 with Milne-Edwards's family of Crevettines, and also 

 with that of Gammaridea of Dana. It is subdivided 

 into VAGANTIA and DOMICOLA. 



Subdivision VAGANTIA. 



The VAGANTIA have always the inferior antennae ter- 

 minating in a flexible multiarticulate flagellum, and the 

 posterior pair of caudal appendages are fringed with fine 

 hairs or short spines, and are never furnished with hooks. 

 They construct no abodes to dwell in, but wander from 

 place to place, swimming or walking in the sea, and 

 hopping or wriggling along upon their sides on land. 



This subdivision represents Milne-Edwards's tribe of 

 Sauteurs. It consists of the two tribes SALTATORIA 

 and NATATQRIA, each consisting of a single family. 



Tribe SALTATORIA. 



In this tribe the posterior caudal appendages are never 

 longer than the two preceding pairs. The hairs upon the 



