2 74 
CRUSTACEANS. 
The tribe Flabellifera contains a part of marine species, in which the abdomen 
terminates in a tail-tin, formed as in the macrurous decapods from the telson and 
the limbs of the last segment. There are too many families to mention, but some 
of the characteristic forms are shown in the accompanying illustrations. In the 
genus Serolis, which alone represents the family Serolidoe, the body is depressed 
and broad, the segments of the thorax being furnished with long pointed side- 
plates, which impart to the animal a superficial resemblance to a trilobite. The 
legs and two pairs of antennse are long. It is stated that the Serolidce “ live by 
preference on sandy ground, into which they burrow with their flat bodies up 
to the caudal plate. Their nourishment appears chiefly to consist of the organic 
materials distributed in the fine sand, diatomacea and organic detritus. Their 
locomotion is carried on less by swimming than by backward movements on the 
sandy ground, wherein the widely separated feet are used as a point of support.” 
The species figured ($. bromleyana ) is the largest, and has been taken at a depth 
of nineteen hundred and seventy-five fathoms. In the Sphceromidce the convex 
body is capable of being rolled into a ball. Several species of Spliceroma occur 
on the coasts of Britain, and may be found, sometimes in numbers, sometimes 
isolated, beneath stones or amongst seaweed at low water. The next family 
(Gnathiidce ) contains the genus Gnathia, in which the males and females are so 
Serolis bromleyana (nat. size). 
