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slender spines; but no traces of the lateral spinules have as yet appeared, nor 
do the uropoda furp) as yet exhibit any armature whatever. No trace of cal¬ 
careous matter has as yet been deposited in the integuments, which of course 
are very thin and pellucid, admitting the inner organs to he traced with great 
distinctness through their walls. The stomach (st) has assumed its characteristic 
form and curvature, and all 3 liver-sacs (1) on each side have been formed ; but 
the upper and lower sac are still very short, scarcely attaining half the lenght of 
the middle one. Behind the carapace dorsally, the heart (h) is easily observable, 
as also the renal organs (n) occurring to each side of it. The intestinal tube 
is still without any contents, and on this account is less conspicuous than in the 
post-embryonal stages. 
When the young is ready to escape from the mother, it has assumed 
much the appearance of the adult animal, and the integuments have been partly 
indurated with calcareous deposits, so as to make them rather hard and intrans¬ 
parent. The only essential difference consists in the absence of the last pair of 
legs. On a closer examination, however, these limbs are found in process of 
development, but enclosed within a conspicuous ventral prominence of the last 
trunk segment. They will accordingly be set free by a subsequent exuviation. 
