102 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [396] 
brown, and often annulated with brown, or with gray and white. It 
differs from all the other American species in having a short, acute ros- 
trum, scarcely projecting beyond the eyes, with three or four sharp teeth 
on its upper edge and none below. In form and general appearance it 
somewhat resembles the Virbius represented in Plate ILI, fig. 11, but is 
stouter and quite different in color. It is a northern species, extending 
to Greenland and Northern Europe, and is more common on the coast 
of Maine, where it is usually associated with several other larger species 
of the same genus, all of which are remarkable for their brilliant colors, 
the various shades of red usually predominating. Their bright colors 
are no doubt directly connected with their habit of living among the 
bright red algie, so abundant in the shallow waters on rocky bottoms. 
A beautiful little shrimp-like Crustacean, Mysis Americana SMITH, 
sometimes occurs in immense numbers among the algze growing on the 
rocks just below low-water mark, especially in spring. This is an im- 
portant species, as it is one of the principal kinds of food for the shad 
and other fishes. The full grown specimens are only about an inch long. 
It is almost transparent, whitish, with conspicuous black eyes; there is 
arow Of more or less conspicuous, dark stellate spots along the body, both 
above and below, and similar specks often occur on the tail; a spot of 
dark brown or blackish often occurs on each side of the carapax. The 
intestine shows through as a greenish or brownish line. 
Another small, shrimp-like species belonging to an interesting new 
genus, the Heteromysis formosa SMITH, often occurred in small colonies, 
sometimes hid away in the dead shell of some large bivalve or gastro- 
pod. The females of this species are of a beautiful light rose color, but 
the males have the pale color and translucency common to most of the 
species of Mysis. 
Numerous Amphipods also occur, most of which are also found in 
the pools or under stones at low water, and have, consequently, been 
mentioned on former pages. One of the most curious Amphipods 
was a small species, found living among the large compound ascidians, 
which is probably Cerapus tubularis Say. This species constructs 
a little, slender, free tube, which it inhabits and carries about 
upon its back when it travels, very much as the larve of caddis-flies, 
common in fresh waters, carry about their tubes. One species of bar- 
nacle, the Balanus crenatus, was abundant, often completely covering 
small stones and shells. This has not been met with, as yet, at low- 
water, although it occurs on the bottoms of vessels. 
Of Annelids a large number inhabit rocky bottoms, but as most of 
them live beneath the rocks, or in tubes attached to rocks and stones, 
itis difficult to obtain an accurate knowledge of them. Many of the 
species seem, however, to be found also in pools and beneath the stones 
on rocky shores, and have already been mentioned. 
Perhaps the most characteristic Annelids of rocky bottoms are the 
scaly worms, of which three species are common in this region, viz.: 
