NATURAI, HISTORY OF AMERICAN LOBSTER. 293 



the reproductive functions are apt to be disturbed. The eggs, instead of being expelled 

 in the natural way, perish in the ovary, possibly by having their requisite supply of 

 oxygen from the blood curtailed, and absorption of this inert mass begins, in part at 

 least, through the agency of the blood. By taking up the green pigment from the eggs 

 the blood becomes very dark in color, thus giving all the tissues an unpalatable greenish- 

 black appearance, very noticeable at the articular membranes. 



The green color of the eggs, like that of all parts of the integument of this animal, 

 is due, as we have seen, to the presence of dissolved pigments of a very unstable char- 

 acter. In consequence of partial absorption and coincident changes in the pigment 

 which remains, the degenerating eggs gradually assume a yellowish-orange color. 

 Whether the animal survives these conditions and succeeds in producing another batch 

 of fertile eggs in due course has not been determined, but the chances would seem to 

 be wholly in its favor. 



While physiological disturbances of this kind are commonly induced by unnatural 

 conditions, a single case has been observed in which the eggs of an animal recently 

 taken from the sea were partially absorbed. Degeneration had spread irregularly 

 throughout the entire organ, which at this stage of the process presented a remarkable 

 appearance, being dark green, marbled with light lemon yellow. All the tissues 

 pervaded by the blood seemed to be steeped in a green dye, which the organism was 

 trying to throw off. 



The structure of the ovaries, as outlined, suggest certain questions of considerable 

 economic interest, such as the age at which sexual maturity is reached, the limits of 

 the breeding season, and the length of the reproductive cycle or the frequency of 

 spawning. We shall endeavor to show what light direct observation and anatomy have 

 shed upon these matters. 



PERIOD OF ADULT LIFE OR SEXUAL MATURITY. 



The age of sexual maturity varies greatly in individuals, extending over an interval 

 in which lobsters vary in length from 7 to ii>^ or 12 inches. Out of thousands we 

 should expect to find here and there one of possibly less than 7 and more than 1 2 inches 

 in length coming to maturity for the first time. We may safely rnnrlnde that the 

 jTiajnrity nf thrnr riinimnh n re mature when 10^ inches long. Very few are with spawn 

 before attaining a length of 8 >^ or 9 inches. In order to test this question traps must 

 be put down at a certain point, kept there for a long period, and the catch noted day 

 by day and month after month. This was done in_ the harbar-at-Wocida Hole. JIaas., 

 wher^_traps were laid by Mr. Vinal Edwar ds December i, 1893, and t he_dail^catches 

 recorded until July i, 1894, the conditions as to molting and the p r esence of eggs be ing 

 noted in" each individual. A summary of the catch showingthe proportion of each 

 sex and the presence of external eggs is recorded in table 9. During a period of 6 months 

 1,344 female lobsters were captured, and of these 168 carried eggs; of 249 females 

 measuring from 6 to 8 inches but 3 bore eggs, while of those under the 9-inch length 

 but 1 1 were berried. 



