TIIE HORSESHOE CRAB. SL>. 



Jeffreys Wyman has sent me specimens collected by himself about sixty-five miles up tin- Saint 

 .luliii's K'iver, in Florida, where the water is not at all brackish. This species is sometimes found 

 adhering to the carapax of Crabs, the shell of Limvlvt, and various mollusks. It is easily 

 distinguished (nun most species on account of its low, broad form and its smooth, white exterior. 

 It has a shelly base. The />'. rrcnatwi, common on shells and stones in deep water, also occurs on 

 vessels. Other species are often found on the bottoms of vessels that have couie from warmer 

 latitudes. Some of them are of large size. One of the most frequent of these is Balantm 

 tintiinuttnilinn." 



232. THE XIPHOSURA 

 THE HORSESHOE CRAB LIMULUS POLYPHEMUS, Latreille. 



The curious form of marine animal called "Horseshoe Crab," "King Crab," and " Horse 

 foot," ranges along our entire Atlantic coast, from Casco Bay, Maine, to Mexico, and gives rise 

 to an important industry in at least one region Delaware Bay. It is not, however, a true Crab, 

 and its exact position in the animal kingdom is still involved in much obscurity. Some natu- 

 ralists regard it as a low type of crustacean, while others place it among the Arachnida, or 

 scorpions and spiders. Its nearest allies all occur as fossils, through many geological ages down 

 to nearly the oldest of the fossiliferous series. Another species of the same genus, however, still 

 lives upon the eastern coast of Asia. 



The carapax of the King Crab is very large, with a regularly rounded outer margin, termi- 

 nating in a spine at the posterior angles on both sides. The abdomen is much smaller, and from 

 its hinder end, to which it is jointed, runs out a long, tapering spine. The basal portions of the 

 feet on the lower side of the carapax serve as masticating organs. 



The King Crab is sluggish in its movements, and spends mnch of its time more or less buried 

 in the mud and sand of shallow water, coming up occasionally to high-water mark. It is most 

 abundant on the muddy bottoms of shores and estuaries, where it burrows just beneath the 

 surface, and feeds upou 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 Rev. S. Lockwood, 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 jteciiliar 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. In aquaria, 

 under favorable circumstances, the eggs hatch in about six weeks, but in their natural conditions 

 they probably hatch sooner than this; under unfavorable conditions the hatching may be delayed 

 for a whole year. The eggs are very numerous."' 



From several intelligent observers living on the Delaware Bay side of Southern New Jersey 

 we have received interesting notes on the habits of the King Crab, as exemplified in that region, 

 and which may also hold good for others. While this Crab is comparatively rare on the outer 

 side of Southern New Jersey, on the inner side, along the shores of Delaware I'.ay. from Cape 

 May to Reed's Island, it is unusually abundant. It is not, however, always present in the very 

 shallow water near shore. During the breeding season, which is mainly confined to the months 

 of May and June, but also extends slightly into .Inly, the males and females approach and ascend 

 the beaches in countless numbers, the latter to lay their eggs, the former to impregnate them. It 



: Vineyard Sound Report, pp. 340, 341, 1871-'72. 



