422 Mr. A. O. Walker on Pherusa fucicola [Leach). 



Boeck, would probably answer quite as well. But a complete 

 revision of the Pleustid^, Atylidae, &c. is much wanted, and 

 until this is done I prefer to disturb existing genera as little 

 as possible. 



I have very little doubt that CalUopius norvegicus, Boeck, 

 should be referred to the above species. Meinert (' Natur- 

 historisk Tidsskrift,' 1877-8) and Zaddach (' Meeresfauna 

 Preuss. Kiiste ') consider that C, norvegicus cannot be distin- 

 guished from C. levi'usculus, Kroyer. In this I cannot agree 

 with them. The two species differ completely in the antennae, 

 the first and second gnathopods, and the form of the hinder 

 margin of the third pleon-segment. The nodule or tooth on 

 the third joint of the peduncle of the upper antenna is only 

 found in the male. 



The type specimen in the British Museum now stands as 

 follows : — 



Genus Gammarella, Bate, 1857. 



Gammarella hrevicaudata, M.-Edwards. 



\_Pherusa fucicola, Leach?] 

 Amphithoe micrura, Costa, /. c. ( 5 )• 



For other synonyms see Norman, Ann. & Mag. Nat. Hist. 1889, ser. 6, 

 vol. iv. p. 128. 



It will be seen that Costa fell into the same error as Leach 

 and Bate and Westwood in overlooking the secondary appen- 

 dage of the upper antennae both in his Amphithoe micrura 

 and A. semicarinata. 



I have to thank Dr. A. M. Norman, F.R.S., and the Rev. 

 T. R. R. Stebbing for valuable suggestions, and Mr. R. I. 

 Pocock, of the British Museum, for his kind assistance in the 

 examination of the type specimens. 



Colwyn Bay, 

 March 20, 1891. 



