320 MARKINGS, FOOTPRINTS AND FUCOIDS 



rare, and not infrequently cast on shore in storms. But the 

 best facilities for studying their habits were found in a marsh 

 at no great distance from the hotel, where there were numerous 

 channels, ditches and little ponds filled with sea water at high 

 tide. In these were multitudes of young Limuli, varying from 

 an inch to three or four inches in breadth, and though many 

 were dead or merely cast shells, it was easy to take young 

 specimens with a landing net. A number of these were se- 

 cured, and I made it my business for some time to study their 

 habits and mode of life, and especially the tracks which they 

 made in sand or mud. 



The King-crab, viewed from above, consists of three parts. 

 The anterior shield or carapace is semi-circular in form, with 

 two spines or projecting points at the angles, raised in the 

 middle and sloping down to a smooth or moderately sharp 

 edge in front. The eyes are set like windows in this shield. 

 Two large ones at the sides, which are compound eyes con- 

 sisting of numerous ocelli or little eyes, and two microscopic 

 ones in front, at the base of a little spine, which are simple. 

 The second or abdominal part is also in one piece, somewhat 

 quadrate in form, with ridges and serratures at the sides armed 

 with spines, and which may be said to simulate the separate 

 joints into which the abdomen of an ordinary Crustacean is 

 divided. The third part is a long tail spine, triangular in cross 

 section, sharply pointed, and so jointed to the posterior end 

 of the abdomen that it can be freely moved in any direction 

 as a bayonet-like weapon of defence. When unable to escape 

 from an enemy it is the habit of the creature to double itself 

 up by bending the abdomen against the carapace, and erecting 

 the sharp spine. Thus, with fixed bayonet it awaits attack, 

 like the kneeling soldier in front of a square. 



Below this upper shield, which is thin and papery in the 

 young, somewhat horny in the adult, are the numerous limbs 

 of the creature, with which we are at present most concerned. 



