340 KEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



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 ^ew 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 

 antennae, 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 a new 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 

 antennae 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 

 cceca (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 mi^iing a little mound at the end of 

 the burrow, w^here the creature can usually be found. This species is 

 whitish, irregularly specked with dark gray, so as to imitate the color 

 of the sand very perfectl^^ It is also 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 Y, 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 Foly- 

 pliemuSj is also an inhabitant of sandy shores, just below low-water mark, 

 but it is 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 

 of Eev. 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 nipi)ers, 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. 



