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PORTUNIDJ3. 



or less. The following are my notes made at the time 

 of observation on one that bred in captivity : ' It seems 

 clear that each ovum has two investing coats, one proper 

 to it, the other in which it is enclosed as attached to the 

 parent. The latter has a thread, a portion of which is 

 seen attached to the ovum after it has been thrown off. 

 The ovum bursts on the sides opposite to this thread, and 

 the creature first protrudes the abdominal portion, or that 

 which is behind the carapace, and which in the ovum had 

 been bent underneath ; so that it escapes backwards. 

 In some it appeared as if the caudal extremity protruded 

 first ; but in most it was the bent portion, and the legs 

 were in general bent up under the thorax. They seemed, 

 however, to find great difficulty in throwing off the loose 

 membrane of the ovum from the thoracic portion or cara- 

 pace, and almost all failed in doing this effectually, the 

 development, perhaps, going on too rapidly, in consequence 

 of exposure to a warm sun. I suppose, that in the na- 

 tural state this is effected in the sand, by creeping back- 

 ward, and thereby rubbing it off. The eyes of these young 

 Crabs, at their first escape from the ovum, are large and 

 sessile. In one or two instances, I thought I saw antennae 

 and branchiae, or, at least, their projecting extremities ; 

 but I could not decidedly distinguish between them and 

 the legs. The thoracic portion, or carapace, is somewhat 

 rounded, or at least ovoid. I could see no chela, and sup- 

 pose them not developed. The common legs seem bifur- 

 cate at the second joint from the extremity, and ending 

 in a fine point; or, perhaps, the bifurcation is at the root. 

 The abdominal and caudal portion is long and narrow, and 

 also projecting, much resembling the corresponding por* 

 tion of the Nebalia Herbstii. A considerable change or 

 metamorphosis, must take place in these creatures before 



