AMPHIPODA 
277 
Order Amphipoda. 
fresh-water shrimp (enlarged). 
The Amphipods are allied to the Isopods, but the majority are recognisable 
by having the body narrow and flattened from side to side, instead of broad and 
flattened below. Moreover, the gills are attached to the thoracic feet, and the 
latter, instead of being 
broad, leaf - like, and 
overlapping, are foot¬ 
like, elongate, and used 
for leaping or swim¬ 
ming;. 
o 
In the suborder 
Gammariclea the eyes 
are mostly of small 
size, and seldom pro¬ 
minent. The head 
does not coalesce with 
the first segment of 
the thorax, and the 
maxillipedes have a distinct palp; the abdomen being well developed, and 
bearing appendages. The form of the body is shown in the illustration of the 
fresh-water shrimp ( Gammarus pulex), and the sand- 
hopper ( Talitrus locusta). The latter lives near the 
edge of the sea, beneath seaweed, or other substances, 
which prevent the evaporation of the moisture from 
the sand. Sand-hoppers usually progress on land by 
leaps; and although some nearly allied forms are 
found far from the sea, the majority of the Gam- 
maridea are marine, swimming by means of the con¬ 
stant play of their abdominal appendages, and, when 
thrown on the land, wriggling helplessly along on their 
sides. The fresh-water shrimp 
is common in the streams and 
ditches of Europe. During 
the cold months of the year 
they bury themselves in the 
mud, but emerge from their 
winter-quarters on the first 
warm days of spring. 
Amongst deep-water forms, 
perhaps the most noteworthy 
are Acanthechinus tricari- 
natus, and Andania gigantea. 
The former has developed a 
spiny process at almost every 
possible point, each of the 
sand-hopper (enlarged). 
spiny shrimp, Acanthechinus tricarinatus (nat. size). 
