296 



BULLETIN OF THE BUREAU OF FISHERIES. 



Sen I 



Ser.ll 



la. 



2b 



Ic 



Id. 



place, criticises as follows: "There is nothing to show that the eggs carried by the 

 lobsters at the beginning of the experiment hatched out naturally and were therefore 

 extruded during the previous year." On the contrary, all were of the class which we 

 call "old egg" or "light egg" lobsters, which taken in June means that these eggs were 

 laid the previous summer, and can mean nothing else, unless the rarely occurring "fall" 

 and "winter" eggs which I have described can reach the hatching point in June, a sup- 

 position still awaiting proof. 

 There is, further, no evidence that 

 the removal of the mechanically 

 attached eggs from a lobster in 

 June alters its physiological con- 

 dition. Mr. Scott says further: 

 "There was no obvious need to 

 kill one lobster each month to 

 discover whether it was going to 

 extrude eggs or not." This would 

 seem to be an obvious conclusion, 

 but it should have been equally 

 clear that this step was taken for 

 another purpose, namely, to follow 

 the changes which were taking 

 place in the ovary itself. The con- 

 dition of the ovary tells us at once 

 whether growth of the ova is active 

 or slow, or whether an absorption 

 of the eggs already formed is going 

 on. The step was far from need- 

 less, for after July it proved that 

 there was no preparation for the 

 production of fall or winter eggs. 

 In other words, it showed that in 

 these animals there was no tend- 

 ency to produce eggs in each of 

 two consecutive years, the chief 

 point in the experiment. It was 

 impossible to foresee how many of 

 these animals would die in the course of their confinement or because of it, but had all 

 of them lived two-thirds of the total number at the start, or 24, would have had a 

 chance to spawn in 13 months from the time the experiment began." 



a The experiment would have been more satisfactory if the directions, which were as follows, had been carried out: " Preserve 

 the ovary of one lobster the first day of each month from July to December. If the number of lobsters should warrant it, con- 

 tinue to preserve the ovaries of one animal from January i until July. If, however, the remaining lobsters are few in number, 

 and do not stand the confinement well, keep all as long as possible, preserving the ovary of each one that dies. * * * In case 

 the lobsters die rapidly in late summer or early autumn, preserve ovaries of those only which die, giving the date." 



2a. 



3a. 



Fig. 30- — Diagram to illustrate growth in a single generation of lobster's 

 eggs during a period of nearly 3 years, from an initial stage in ovary to 

 time of hatching. Ser. i, internal or ovarian eggs; Ser, n, external or at- 

 tached eggs. I a, ovarian egg immediately after egg-laying; i b, the same, 

 15 days after; i c, the same 42 days after; i d, the same i year after; 2 a, the 

 same in second growth period, i year and 10 months after egg-laying; 2 b, 

 fresh laid egg; 2 c, "strictly" fresh, but removed from, ovary or duct; 3 a, 

 last period of growth in shell, or egg-embryo about to hatch. Sizes de- 

 duced from averages of 10 eggs in nearly every case. Enlarged about 20 

 diameters. 



