Development of Estheria Packardi. 13 



the dorsal face of the trunk in more than half its length. 

 The lateral parts are of rounded form, and advance over 

 the greater part of the developing legs. Dorsally, they still 

 . pass immediately into each other, but posteriorly they are 

 separated by a deep incision. Anteriorly the carapace is 

 also well denned, and between it and the anterior division 

 of the body a rather deep impression occurs (see fig. 3). 

 The shell-gland is best seen in the lateral view of the 

 larva (fig. 3), and has nearly assumed its definitive structure. 



The anterior, or cephalic part of the body is scarcely 

 half as long as the posterior, and has the dorsal face still 

 strongly convex above. In a lateral view of the larva (fig. 3), 

 it appears almost transversely truncated in front, with the 

 anterior edge somewhat flexuous, exhibiting a slight bulging 

 at the place inside which the compound eye is developing. 

 The lower corner, in front of the antennulæ, is somewhat 

 projecting, but no trace of a true rostrum is as yet to be 

 detected. The posterior division, as in the preceding stages, 

 is gradually narrowed distally, and has the furcal pro- 

 cesses more fully developed, with the secondary denticle 

 larger. At some distance in front of the latter is seen 

 dorsally a slight angular prominence, and below it the caudal 

 setæ are about to grow forth. 



The ocellus, labrum and Nauplian limbs are, on the 

 whole, unchanged, except that the outer ramus of the an- 

 tennae exhibits a trace of an articulation. 



The branchial legs, of which, in the preceding stage, 

 only 4 pairs of bud-like rudiments were found, appear now 

 more fully developed. They have, moreover, increased to 

 6 pairs, rapidly diminishing in size posteriorly, the last pair 

 being still rather small. On all the legs the 3 chief parts, 

 the exopodite, endopodite and epipodite, may now be 



