46 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [340] 
It is also occasionally found under stones in sandy places. Its color is 
pale yellowish white. The Unciola irrorata (Plate IV, fig. 19) often 
lives in tubes in the sand in abundance, but is by no means confined to 
such localities, for it occurs on all kinds of bottoms and at all depths 
down to at least 430 fathoms (off St. George’s Bank,) and is abundant 
all along the coast, from New Jersey to Labrador. It is particularly 
abundant on shelly and rocky bottoms, and although it habitually lives 
in tubes, it does not always construct its own tube, but is ready and 
willing to take possession of any empty worm-tube into which it can 
get, and having once taken possession it seems to be perfectly at home, 
for it remains near the end of the tube protruding its stout claw-like 
antenne, and looking out for its prey, in the most independent manner. 
It will also frequently leave its tube and swim actively about for a time, 
and then return to its former tube, or hunt up anew one. It seems, 
however, to be capable of constructing a tube for itself, when it can- 
not find suitable ones ready-made. Its color is somewhat variable, but 
it is generally irregularly specked with red and flake-white, and the 
antenus are banded with red. It contributes very largely to the food 
of many fishes, such as scup, pollock, striped bass, &c. 
On the moist sand-flats curious crooked trails made by the Idotea 
ceca (Plate V, fig. 22) may generally be seen. This little Isopod bur- 
rows like a mole just beneath the surface of the sand, raising it up into 
a little ridge as it goes along, and making a little mound at the end of 
the burrow, where the creature can usually be found. This species is 
whitish, irreg ularly specked with dark gray, so as to imitate the color 
of the sand very perfectly. It isalso capable of swimming quite rapidly. 
The Idotea Tuftsii is another allied species, having the same habits and 
living in similar places, but it is much more rare in this region. It has 
also been dredged on sandy bottoms off shore. It is a smaller species 
and darker colored, with dark brown markings. The Idotea irrorata 
(p. 316, Plate V, fig. 23) also occurs on sandy shores wherever there is 
eel-grass, among which it loves to dwell. 
The well known “horseshoe-crab” or “king-crab,” Limulus Poly- 
phemus, is also an inhabitant of sandy shores, just below low-water mark, 
but itis more abundant on muddy bottoms and in estuaries, where it 
burrows just beneath the surface and feeds upon various small animals. 
At the breeding season, however, it comes up on the sandy shores to 
deposit the eggs, near high-water mark. According to the statements 
ot Rev. S. Lockwood, (in American Naturalist, vol. iv, p. 257,) the 
spawning is done at the time of high tides, during May, June, and July; 
they come up in pairs, the males, which are smallest, riding on the 
backs of the females and holding themselves in that position by the 
short feet, provided with nippers, which are peculiar to the males. The 
female excavates a depression in the sand and deposits the eggs in it, 
and the male casts the milt over them, when they again return to 
deeper water, leaving the eggs to be buried by the action of the waves. 
