CRUSTACEA. 
Ill-AMP HTP OT)A. ( 
By A. 0. Walker, F.L.S. 
(13 Plates.) 
The collection of Amphipoda consists of fifty-three species, of which eighteen are new 
to science, belonging to forty-three genera, of which four are new. This may not appear a 
very large number considering the length of time the ‘ Discovery ’ was in the Antarctic 
Seas, yet as (with the exception of the pelagic Hyperiids taken on the voyage) all but some 
nine species were collected from holes in the ice at the Winter Quarters, and, therefore, from 
a very limited area, it appears to me to reflect great credit on the energy and persever¬ 
ance of Mr. Hodgson under unusual climatic conditions. The long sojourn of the 
‘ Discovery ’ in one spot enables us to observe the seasons at which different species 
visit shallow water, generally for the purpose of depositing their ova or young. In the 
case of the most abundant species, Orchomenopsis rossi, A. 0. W., of which Mr. 
Hodgson says that “ It was quite the usual thing to take ten to thirty thousand at a 
haul,” I only observed one male with fully developed lower antennae and no females with 
ova, though some measured as much as 25mm. The young had probably been born 
at a considerable depth, and had at once made their way to comparatively shallow 
water, the parents remaining in deep water. Again, the almost equally abundant 
Eusirus propinquus (G. 0. Sars) only exceeded 25mm. in four specimens, three females 
with ova or young measuring 48mm., and one male measuring 50mm. This species 
resembles in this respect Gammarellus \_Amathilla ] homari (Fabr.), which I have 
observed to visit the north coast of Wales in the early spring, when alone the large 
adult females, and more rarely males, measuring nearly tin. in length, can be taken 
between tide-marks ; in the summer months every tidal pool swarms with young 
specimens. 
As in the Arctic Amphipoda, the Lysianassidse greatly preponderate in the number 
of genera, species, and individuals. The typical Gammaridse, as restricted by Mr. 
Stebbing in establishing the families Melphidippidse and Lilljeborgidse, are unrepre¬ 
sented. In Professor G. 0. Sars’ Amphipoda of Norway there are nine genera with 
twenty-one species ; and in Professor Herdman’s Ceylon collection seven genera with 
fifteen species. 
Among the Gammaridse several species are remarkable for their wide distribution : 
Ampelisca macrocephcila (Lilljeborg) is an abundant Arctic species, though found also in 
e 2 
