Crustacea and Pijcnogonida. 47 



probably to be referred to the male or horealis form of //. 

 jjolarisy in which the rostrum is entirely devoid of teeth on 

 its upper margin, and possesses but a single small tooth on the 

 lower margin. The larger flagellum of the antennules is con- 

 siderably thickened. Tiie anterior margin of the carapace is 

 armed with a supraocular and infraocular spine. Prof. S. I. 

 Smith, it may be observed, has noted that in extreme varie- 

 ties of H. ipolaris the rostrum is wholly edentulous. 



Amphipoda. 



Anonyx nugax (Phipps). 



Numerous specimens of this, perhaps the commonest Arctic 

 Amphipod, were collected. 



Acantho7iotozoma injlatum (Kroyer). 



A single female was obtained. This specimen agrees very 

 well with Goes's figure of the species ; but the anterior margin 

 of the coxa of the fourth thoracic limb is regularly rounded, 

 whereas in Goes's figure it is represented as somewhat angu- 

 lated. The dorsal carina, which is described by Boeck as 

 very high (altissima)^ on the first three postabdominal seg- 

 ments, in Goes's figure and in our specimen is distinct, but 

 not much elevated. 



Acanthostejjlieia pulchra^ sp. n. 

 (PI. VII. figs. 1, 2.) 



Body robust. Head, as in A. MaJmgreni, armed with a 

 long dorsally, inferiorly, and laterally carinated rostrum, which 

 is somewhat curved downward toward the apex, and is pro- 

 longed beyond the distal end of the first exposed joint of the 

 superior antennae ; posteriorly the dorsal keel of the rostrum 

 is prolonged backward between tlie eyes to the posterior margin 

 of the head. Each of the segments of tlie body present, indi- 

 cations of a median dorsal carina, which is elevated in the 

 form of a single obtuse somewhat triangular lobe on the fifth 

 and sixth segments, and forms two lobes on the seventh seg- 

 ment ; two similar lobes exist on each of the first four seg- 

 ments of the postabdomen ; but the lobes, although acute, are 

 not so greatly produced backward, and on the fourth segment 

 a much greater interval exists between the first and second 

 of the dorsal lobes in A. 2yulchrai\\ix\\ in A. Mahngrem. The 

 postero-lateral angles of the sixth and seventh segments of the 

 body and of the first three segments of the postabdomen are 

 regularly rounded — not, as in A. Mahngrem, produced into 

 spines. The superior antenna are relatively shorter than in 



