159 



defined inferiorly by a sharp upturned denticle, below which sometimes occur 

 2 or 3 minute serrations. Antennae about as in H. trim c fa, but with a smaller 

 number of articulations in the flagella. (xiiathopoda likewise of a very simi- 

 lar structure, the posterior ones being considerably more powerful than the 

 anterior, with the thumb-like process rather strong. Penultimate pair of 

 pereiopoda extremely slender and elongated, equalling in length 3 A of the 

 body; basal joint of last pair with the posterior expansion obliquely deflexed 

 and rounded, edge bearing long slender setae and having between them about 

 12 serrations, the inferior of which are more or less distinctly bipartite. Last 

 pair of uropoda with the inner ramus scarcely exceeding half the length of 

 the basal joint of the outer; the latter with only 3 spines exteriorly; each 

 ramus tipped by a single slender seta. Lobes of telson less diverging than in 

 H. fmncata and narrowly rounded at the tip. - Adult male rather like in 

 outer habitus that of H. neglecta and pectinata, but differing in the fuller 

 development of the oral parts, the structure of the gnathopoda, which nearly 

 agrees with that in the female, by the not-produced last pair of epimeral 

 plates of metasome, and by the outer ramus of the last pair of uropoda being 

 considerably longer than the inner. Colour greyish white, pellucid. Length 

 of adult female scarcely exceeding 4 mm, of male about the same. 



Hem-arks. - The description at first given by Boeck of this species, does 

 not fully correspond with his figures, and it is most probable therefore, that he 

 has confounded it with another species, perhaps the form described above as 

 H. pectinata. As however the figures subsequently given in his great work on 

 the northern Amphipoda undoubtedly relate to the present species, the specific 

 name crenulata at first proposed ought to be retained for this form. The 

 species may be readily distinguished by the great length of the penultimate 

 pair of pereiopoda, the peculiar shape and armature of the basal joint 

 of the last pair, and by the form of the last pair of epimeral plates of the 

 metasome. 



Occurrence. - - Off the south and west coast of Norway, this species 

 is by no means rare, occurring, together with H. neylecta and pecthtata, in 

 depths varying from 30 to 100 fathoms. I have also collected it rather 

 abundantly in the Trondhjemsfjord, and Mr. Schneider has found a single 

 specimen in the neighbourhood of Troinso, Finmark. 



Distribution. Kattegat (Meinert); coast of Bohuslan (Stockholm 

 Museum). 



