DEVELOPMENT OF Till: YOUNG. 801 



female Lobsters coiiflncd iu the well. Some of these specimens lived in vessels of fresh sea-water 

 for two days, but all efforts to keep them alive long enough to observe their molting failed. They 

 appeared, while thus in confinement, to feed principally upon very minute animals of different 

 kinds, but were .several times seen to devour small Zoeae, and occasionally when much crowded, so 

 that some of them became exhausted, they fed upon each other, the stronger ones eating the 

 weaker. 



"Second stage. In the next stage the young Lobsters have increased somewhat in size, and 

 the abdominal legs of the second to the fifth segments have appeared. The rostrum is much 

 broader and there are several teeth along the edges. The basal segments of the antenuulae have 

 become defined, and the secondary flagellum has appeared, but is not subdivided into segments. 

 The autcnuiB and mouth organs have undergone but slight changes. The first cepbalo-thoracio 

 legs are proportionally larger and stouter than in the first stage, and have become truly cheli- 

 forrn. The succeeding legs have changed little. The epipodi of all the legs and of the external 

 maxilhpeds have increased in size, and the branchial processes are distinctly lobed along the 

 edges, and have begun to assume the form of true branchiae. The segments of the abdomen have 

 the same number of spines, but they are relatively somewhat smaller, and the last segment is 

 relatively -smaller and broader at base. The appendages of the second to the fifth segments differ 

 considerably in size indifferent specimens, but are nearly as long as the segments themselves; 

 their terminal lamella?, however, are represented only by simple, sack-like appendages, without 

 sign of segmentation, or clothing of hairs or set. The penultimate segment is still without 

 appendages. Specimens in this stage were taken only twice, July 1 and 15. They have the same 

 habits and general appearance as in the first stage, but are readily distinguished by the posses- 

 sion of rudimentary abdominal legs. In color they are almost exactly the same, only the orange- 

 colored markings are perhaps a little less intense. 



" Third stage. In the third stage the larvae are about half an inch (12" 1111 to 13 mm ) in length, 

 and the integument is of a much firmer consisteny than in the earlier stages. The antennuItB are 

 still rudimentary, and considerably shorter than the rostrum, although the secondary flagellum 

 has increased in length and begins to show division into numerous segments. The antennae 

 retain the most marked feature of the early stages the large size of the scale but the tiagellum 

 is much longer than the scale and begins to show division into segments. . . . The external 

 inaxillipeds have begun to lose their pediform character. The anterior legs have increased 

 enormously iu size, and those of the second and third pairs have become truly chelate, while the 

 swimming exopodal branches of all the legs, as well as of the external maxillipeds, are relatively 

 much smaller and more unimportant. . . . The branchiae have developed rapidly and have 

 a single series of well-marked lobes along each side. The abdomen still has the spines charac- 

 teristic of the earlier stages, though all of them are much reduced iu size. The appendages of 

 the second to the fifth segments have become conspicuous, their lamellae have more than doubled 

 in length, and the margins of the terminal half are furnished with very short ciliated setae. The 

 appendages of the penultimate segment are well developed, although quite different from those in 

 the adult. The outer lamella wants wholly the transverse articulation near its extremity, and 

 both are margined, except the outer edge of the outer lamella, with long plumose hairs. The last 

 segment is relatively smaller and more quadrangular in outline, and the spines of the posterior 

 margin are much smaller. The only specimens procured in this stage were taken July 8 and 15. 

 In color they were less brilliant than iu the earlier stages, the orange markings being duller and 

 the whole animal slightly tinged with greenish-brown. 



" In the next stage observed, the animal, about three fifths of an inch (W"" to 17 mm ) long, has 

 51 F 



