./ ''Living FossiF' 229 



and sixth pair, the base of each of the others is set 

 with sharp, bristhng spines, which, like jaws, macerate, 

 or tear the food before it is swallowed. 



The operculum acts as a covering for the abdominal 

 appendages, of which there are five pairs and which 

 resemble it in form. These support the gills. The 

 pairs overlap each other to some extent, and each 

 appendage is composed of a broad, thin plate having on 

 its rear surface large leaflike and membranous folds to 

 which are relegated the function of respiration. 



Before proceeding with the development of the 

 famous young of Limulus, it may be well for us to 

 observe what part the parents play in their destiny. To 

 this end, therefore, let us see what the beach has in 

 store for us. On my visits there, early in May, when 

 the waters of this latitude have lost their intense win- 

 tery chill, I find the horseshoe crab making its first 

 appearance. Throughout the season of cold, it has 

 sought the safety and seclusion afforded by the outer 

 floor of the harbor, where it lies dormant, not, it would 

 seem, buried underneath, but resting somnolently on 

 the bottom. This fact is evidenced by the inordinately 

 heavy growth of hydroids, barnacles, and plants which 

 cover the carapaces of so many returning migrants: a 

 condition that is impossible in an active underground 

 life. The little ones of the tide pool, also, have begun 

 to show themselves. They have, in fact, never left its 

 precincts. With the onset of winter, they dug them- 

 selves in on the spot; and now,Jn common with their 

 elders and many other creatures of the land and sea, 

 they are aw^akened by the arrival of warmer weather 

 into renewed activity. In the quiet enclosure may be 



