Chapter IX.— REPRODUCTION. 



Since every attempt at the artificial propagation or rearing of animals must be 

 made in imitation of nature, the more exact our knowledge of the reproductive 

 life and habits of old and young the more likely are we to succeed. Apart from their 

 economic bearings, however, the problems suggested are the most interesting with 

 which the zoologist has to deal. In the case of many animals the facts which lie at 

 the surface can be gathered and utilized with comparative ease, while in others, as 

 with the common eel, whose breeding habits baffled naturaUsts for centuries, oppor- 

 tunities for making the essential observations are seldom, if ever, presented. In some 

 respects the lobster belongs in the latter class; its life is spent at the bottom of the sea, 

 and when confined in aquaria, where alone continuous observation is possible, the normal 

 play of its reproductive functions is apt to be disturbed. While much attention has 

 been given to the subject, and many important facts have been learned, there are 

 certain questions to which a confession of ignorance is the best answer that can be 

 given. In reviewing the matter in hand we shall endeavor to make it clear whenever 

 a plausible conjecture is offered in place of well-attested facts. 



SEXUAL DISTINCTIONS. 



In general form and color the sexes agree so perfectly as to be indistinguishable 

 to an inexperienced eye when examined from above. The female abdomen is relatively 

 broader than that of the male in adaptation to the protection and safe carriage of the 

 eggs, while length for length the male is heavier, this advantage in weight being seen 

 in his slightly larger claws. Above the 8-inch size, as we have already observed, males 

 are usually heavier than females of the same length, even when the latter carry eggs. 



Upon turning the animal over, the sex is readily determined by a glance at the 

 swimmerets, the first pair of which is rudimentary in the female, and bears but a single 

 hairy blade, the endopodite (fig. i, pi. xxxix). This may be considered as an adaptation 

 for the benefit of the eggs, for were these appendages of normal size they would catch so 

 many ova at the time of spawning as to make it impossible for a large animal com- 

 fortably to fold her tail, a difficulty actually experienced by egg-bearing lobsters over 

 i6 inches long. The seminal receptacle appears as a bright blue shield wedged between 

 the bases of the last two pairs of thoracic legs on the underside of the body. (PI. xxxiii, 

 and fig. 4 and 6, pi. xlih.) Its function is to receive and hold the sperm until the eggs 

 leave the body and are ready for fertilization. Just in front of this organ the oviducts 

 open close together on the basal segments of the second pair of small claw feet. Each 

 duct is closed by a valve and faces its fellow with an incUnation backward. When 

 the eggs are emitted from the mouths of the ducts their natural course in the case of an 

 animal lying on its back would be downward and backward over the seminal receptacle. 

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