53 GAMMARTD^. 



Structure, the head, much of the posterior part of the 

 body, and all the legs and other appendages. 



In the absence of an articulated appendage to the 

 mandibles, and the vmibranched termination of the 

 posterior pair of caudal appendages, some of the genera 

 approximate to the Okchestiid.^, whereas others gradu- 

 ally approach the forms of the next sub-family of the 

 Gammarid^. 



There are but two genera which represent this sub- 

 family upon the British coasts, all the rest being exotic. 

 Some species of Stenothoe, a genus that differs from 

 Montagua in no -very marked degree, fovuid upon the 

 coast of the United States, bear a representative rela- 

 tion to the British forms. 



