254 GAMMARID.E. 



shape. The antennae are nearly of the same length, 

 being about half as long as the animal : the in- 

 ferior pair are the shorter of the two, but their 

 peduncle is longer than that of the superior pair. 

 The arms resemble each other, and are nearly of the 

 same size, the second pair being slightly smaller than 

 the last pair. The last pair of caudal appendages reach 

 considerably beyond those of the two preceding pairs ; 

 the terminal branches are of the same length, and have 

 the margins ciliated. The caudal central plate is long 

 and narrow. 



In the Catalogue of the British Museum Mr. Spence 

 Bate has described a species under the name of Ph. 

 cirrus, which differs from Ph. bicuspis in having the an- 

 tennae shorter, and remarkable in having the upper 

 margin of the peduncle of the inferior antennae fur- 

 nished with several tufts of short hairs, placed at tole- 

 rably regular distances apart ; but upon reconsideration, 

 we believe that Ph. cirrus can only be regarded as 

 a variety of the present species, which was established 

 by Kroyer upon a specimen taken on the coast of Green- 

 land. 



We have had specimens sent to us by Mr. Edward, 

 from Banff; by Mr. Webster, from Tenby and Fal- 

 mouth ; and in the collection of the late Mr. Thomp- 

 son, of Belfast, which has been kindly entrusted to 

 Mr. Westwood for this work, are several specimens 

 which were dredged in Belfast Bay, Sligo, and Bangor 

 (co. Down), in from six to ten fathoms of water. 



In examination under the microscope, we could per- 

 ceive nothing remarkable in the structure of the integu- 

 ment of this animal. 



