No. 2.] EMBRYOLOGY OF THE AMERICAN LOBSTER. 217 



me probable that the eggs of Homarus are fertilized as they 

 leave the oviducts and enter the sea-water. 



Several attempts to find possible canals leading from the 

 receptive apparatus to the ovary have invariably failed, as might 

 be expected. How the spermatozoa can leave the capsules and, 

 at the wish of the female, enter the oviducts by way of the sea- 

 water, is certainly not clear. We have, moreover, according to 

 the report of Spence Bate ('80), the established fact that, at the 

 time of oviposition in the cray-fish, spermatozoa are abundantly 

 found mixed with the eggs ; copulation having occurred some 

 time, ten to forty-five days, previously. The presence of polar 

 globules in the external eggs of Homarus would also argue in 

 favor of external fertilization. 



Data collected during the past summer go to show that the 

 female lobster, as already noted, is charged with spermatozoa 

 from a time long before sexual maturity, a year if not two years 

 before the eggs are actually deposited ; and from that time on, 

 even while carrying fresh eggs or those about to hatch, she inva- 

 riably has stored away in her capsule a certain quantity of male 

 cells. Whether her supply is regularly and periodically in- 

 creased, or whether she is impregnated once for all, I am unable 

 to decide. 



Oviposition and Incubation. 



It is a peculiar fact that, though the lobster has been for cen- 

 turies a staple article of the markets, its time of egg-laying and 

 its period of incubation have not been definitely known. That 

 more light might be thrown on these points, I have carried on 

 quite an extended series of observations, the result of which I 

 subjoin : — 



The eggs are normally deposited during the months of July 

 and August, and develop rapidly so long as the water is rela- 

 tively warm. If the water remains unusually warm- during the 

 fall, certain precocious eggs, as, for example, those mentioned 

 by Rathbun (86), may possibly hatch. Such, however, is not 

 the rule, for I have taken lobsters in October with eggs far 

 advanced, and have exposed them to the wash of the sea from 

 the time of capture through the winter, and even until spring, 

 the eggs in the meantime not hatching and showing but very 

 little advance in development. Large numbers of eggs col- 



