THE AMERICAN LOBSTER. fit 



only .'ilitnit 50 young ours were observed. The remainder of the eggs arc still in jars in good condi- 

 tion. A few of the embryos were transferred to an aquarium with running water, and others to a 

 small vessel iu which there was no change of water. The former lived about 24 hours, the latter about 

 :i(i hours. The temperature of the water in the hatching jar November 5 was 54.3° F. ; on the 6th, 

 55°; and on the 7th and 8th, 56°. * The conditions under which the eggs were kepi were 



perfectly normal, the water being of about the same temperature as that of the harbor outside. 



I have learned of another very interesting case of the artificial hatching of the 

 eggs of the lobster out of the regular season. This happened during the latter part 

 of January and the first ten days of February, 1889, at the hatchery of the United 

 States Fish Commission at Ten Pound Island, Gloucester, Massachusetts. Mr. E. M. 

 Bobinson, to whom I am indebted for these facts, was at that time superintendent of 

 the station. He says that the eggs were clipped from the lobster at about Christmas 

 time, and suspended in aquaria through which sea water was constantly running. 

 The temperature of the water was very low, at least as low as 36° F., and as many as 

 10,000 lobsters were hatched under these conditions. 



Mr. IS i el sen, who visited the station at that time, corroborates this account, so 

 far as the actual hatching of young lobsters is concerned. He writes that he examined 

 with the microscope a young lobster which had been hatched on the day of his visit. 

 The larva had perished in breaking out of the egg and in passing its first molt, but 

 was perfectly developed iu every way. 



These facts clearly show that the hatching period varies in the same way that the 

 time of egg-laying varies. The one must be correlated with the other. 



William H. Wheildon gives some interesting facts about the lobster in a short 

 paper published in 1875 {202), already referred to. He says: 



In February of the present year we exhibited spawn in several stages of development from newly 

 laid eggs to the swimming larvse. 



The fact that the lobsters are with eggs in every month of the year, and that young 

 sometimes make their appearance in winter and fall, does not prove, however, as this 

 writer, like so many others, inferred, that the animal has no particular breeding season, 

 but from these facts alone it would never have been possible to have arrived at a clear 

 understanding of the reproductive habits. To the circumstance that egg-lobsters are 

 taken at all seasons and often with eggs in very different stages of development is 

 due, more than to anything else, the confusion which had settled down upon this most 

 important phase in the life-history of this animal. 



In the case of the lobsters hatched at Woods Hole in early November, 1885, the eggs 

 were probably laid in the late winter or spring of the same year. I have the record 

 of a lobster which had in all probability spawned as early as June 20 (table 3, No. 2). 

 Supposing these ova to have been extruded by the first week in June, they would 

 have had five months, including the warmest period of the year, for their development. 

 For five months, from the first of December to the first of May, the eggs are subjected 

 under natural conditions to a relatively low temperature, and their development is 

 greatly retarded. Consequently a batch of eggs which is extruded at the first or 

 middle of August and hatched in May or June following is not, in all probability, 

 subjected to a greater number of heat units than eggs which are laid in June and 

 hatched in November. The embryos grow very slowly during the winter months, but the 

 advancement may be sufficient, when development has already proceeded far enough 

 in the fall, to bring the embryo to the point of hatching under favorable circumstances 

 in winter. 



