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Limulus deposits its eggs near high water mark in clean, fine sand. 

 In the few instances I have observed the discharge of the sexual pro- 

 ducts, the pair — the male firmly attached to the abdomen of the female 

 — was half buried in sand, covered by three or four inches of water. 

 In one instance that I observed a milky cloud of spermatozoa suddenly 

 appeared around the male, and at about the same time the eggs were 

 probably discharged into a space filled with water under the abdomen 

 of the female. Such a space certainly occurs, for one could see by the 

 currents of water escaping from the apex of the slit between the thorax 

 and abdomen, that the gills of the female were moving freely. When 

 the cloud of spermatozoa appeared the abdominal appendages of the 

 female worked with much greater vigor, stirring up the eggs, sand and 

 spermatozoa. 



During this process none of the eggs escape from beneath the 

 carapace of the female. On turning the pair over I found the eggs 

 thoroughly mixed with sand beneath the abdomen of the female. If 

 undisturbed the pair ploughs forward to a new spot to repeat the ope- 

 ration. Meantime the sides of the excavation fall in covering the eggs 

 with from three to six inches of sand. 



In some cases an excess of a gelatinous secretion, probably derived 

 from the walls of the oviducts, is deposited with the eggs binding them 

 together in large compact masses an inch or more in diameter. Such 

 eggs are usually surrounded by blackened sand that smells strongly of 

 sulphuretted hydrogen. Some of these eggs do not develope at all and 

 many of the remaining ones are abnormal. These conditions are pro- 

 bably due to lack of fertilization of the eggs in the first place, and 

 also to the lack of circulation of pure water through the dense e^^ 

 masses. 



This preliminary statement is necessary in order to understand the 

 difference between the natural conditions and the artificial ones now 

 to be described. 



The eggs to be fertilized are scooped out from the sides of the 

 carapace, washed in sea water to remove clots of blood and then trans- 

 ferred to a perfectly clean shallow glass dish. The latter is slowly 

 tilted from side to side, and as the eggs come in contact with the clean 

 surface they stick there firmly until the whole dish is beautifully lined 

 with a very compact single layer of eggs. The eggs are now washed 

 again to remove any remaining clots of blood and immature eggs, and 

 then covered for two or tree hours with water containing plenty of 

 spermatozoa. After fertilization the eggs require very little attention. 



As the eggs are either spherical or slightly oval and apparently 

 of equal density throughout, it is obvious that if they have any prede- 



