AMPHIPODA OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 187 



Genus TRYPHOSITES G. 0. Sars, 1891. 



TryphofAtes stebbingi (Walker). 



Hoplonyx stebbingi Walker, 1903A, p. 52, pi. ix. figs. 52 to 57. 

 Tmetonyx stebbinr/i Stebbing, 1906, p. 720. 

 Chilton, 1909A, p. 618. 



Station 411, Coats Land, lat. 74 1' S., long. 22 W. ; 161 fathoms. Many 

 specimens, about 17 mm. long. 



I have compared these specimens with those from the Southern Cross Expedition 

 on which Mr WALKER established the species, and find that they agree closely in all 

 points, except that the lateral process of the head might almost be called acute instead 

 of " point rounded " in some of the Southern Cross specimens it is almost or quite as 

 acute as in the Scotia specimens. The first segment of the urus is slightly compressed, 

 but hardly sufficiently so to be called carinate. The eyes are very indistinct or absent 

 completely. The first gnathopod has the propod slightly narrowed towards the distal 

 end, with the palm short and not well defined ; in one specimen the palm was found to 

 be rather oblique on one side of the body, while on the other it was almost transverse ; 

 the dactyl has a prominent secondary nail. In this specimen the second uropod had 

 the inner branch somewhat constricted towards the distal end, as shown by STEBBING 

 for Tryphosa cicadoides (1888, pi. iv. fig. w 2 ) ; the telson is long and narrow, without 

 marginal spinules, but with two small spinules in the emargination at the end of 

 each lobe. 



The species appears to be close to T. cicadoides Stebbing, one of the chief differences 

 being apparently in the shape of the telson ; but it is to be noted that the drawings of 

 the telson of the two specimens represented on plates iv. and v. of the Challenger Report 

 differ to some extent. 



The species was described by WALKER under the genus Hoplonyx, and compared 

 with H. kergueleni (Miers), which is now placed under Tryphosa, the genus to which 

 T. cicadoides was first assigned. Tryphosa kergueleni is certainly not unlike Tmetonyx 

 Stebbingi, but differs in the points mentioned by WALKER, and particularly in having 

 the propod of the first gnathopod stouter and with the palm regularly rather oblique. 

 The first gnathopod of Tryphosa trigonica, as figured in the Challenger Report, is more 

 like that of T. stebbingi, and in describing that species Mr STEBBING suggested that it 

 was perhaps the young of T. kergueleni (Miers). 



In the Scotia specimens, and also in those collected by the Southern Cross, the 

 epistome is produced anteriorly into an acute process as in Tryphosites longipes (Bate 

 and Westwood), and the species must be placed in the same genus, though the 

 differences between Tryphosa, Tmetonyx, and Tryphosites are very trifiing. Tryphosites 

 stebbingi appears to be very close to T. longipes of northern seas, differing chiefly in 

 having the peraeopoda shorter and stouter and the eyes indistinct. 



(BOY. soc. BDIN. TBAKS., VOL. XLVIII., 469.) 



