450 APPENDIX II 
nent part in all these shrimps is here arranged in obliquely trans- 
verse lines or bars on the body, and in specks, blotches, or rings 
on the legs. 
In the numerous species of Spirontocaris, the body is shaped 
as in the preceding, but the beak is much shorter and variously 
shaped and toothed, but always thin and compressed. The first 
pair of legs have small but well-defined claws; those of the second 
pair are notable in being very slender and in having the wrist or 
antepenultimate segment divided into many small pieces jointed 
together and tipped with a minute claw. 
Besides the true shrimps there swarm at the surface numbers 
of transparent schizopods, or cleft-footed shrimps, known as 
M ysis, which swim in immense shoals, and form the main food of 
the sea-trout. These shrimps are of small size, an inch or less 
in length, with large, dark eyes, and have seven instead of five 
pairs of trunk-legs, devoid of claws, but each provided with an 
appendage adapted for swimming. The eggs are carried by the 
female in a marsupial pouch beneath, which has suggested the 
name of “‘opossum-shrimp.” 
The Cumacea are still smaller crustaceans, half an inch or less 
in length, distinguished by having the anterior half very robust, 
the posterior half slender, the eyes sessile, not stalked as in the 
crabs and shrimps, the carapace leaving five segments of the trunk 
exposed, the antepenultimate segment of the body the longest, 
the tail fan composed of three branches. They are abundant in 
sand at the depth of a few fathoms. 
The Phyllocarida, or leaf-shrimps, so called on account of the 
laminar or leaflike expansions with which their legs are provided, 
are represented by Nebalia bipes, which was dredged by Dr. Pack- 
ard at the mouth of Henley Harbour in four to twenty fathoms. 
This little creature, less than an inch in length, is most remarkable 
for the great size of its ancestors, whose paleozoic remains measure 
nearly two feet. 
The Amphipods, or sand-fleas, are by far the most abundant 
of the Crustacea, both in species and individuals. They are found 
on the sand near high-water mark, in seaweed, and among rocks 
in shallow water, and may be dredged at any depth. None is of 
large size; individuals range from about one-eighth of an inch to 
an inch. Many of them hop like fleas. Others move rapidly 
while lying flat. They act as scavengers, often nearly consuming 
a dead fish before it can be hauled in. They are sessile-eyed, 
laterally compressed, somewhat crescent-shaped, with rounded 
backs, and usually of stout build. An exception is the slim skele- 
ton-shrimp, Caprella, which clings to finely branched seaweed 
and is so flexible that it can bend itself into a ring. Ancther 
