. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. tut* specimen was 94 mm. long; of which the head measured mm., the thorax 80 mm., and the abdomen mm. The next older specimen (Z?) shows a marked advance in development over "A" (Fig. 2). The cephalothorax and thorax are no longer distinctly demarked from one another and the sides of the anterior portion of the former region are inflated so that a "head" is differen- tiated. On the dorsal surface, in the neigh- borhood of the antennae, a trace of the borders of the cephalo-thorax still persist. I
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. tut* specimen was 94 mm. long; of which the head measured mm., the thorax 80 mm., and the abdomen mm. The next older specimen (Z?) shows a marked advance in development over "A" (Fig. 2). The cephalothorax and thorax are no longer distinctly demarked from one another and the sides of the anterior portion of the former region are inflated so that a "head" is differen- tiated. On the dorsal surface, in the neigh- borhood of the antennae, a trace of the borders of the cephalo-thorax still persist. In the region of the anterior pair of thoracic limbs, behind the newly-formed "head" a pair of blunt horns have made their ap- pearance. The median eye was not noted in this individual. The antennae and maxil- lipeds are much the same as in stage " A," except that the second antennae are now more chelate. The rostrum is distinctly shifted toward the anterior border of the head and the median tubercule is now rein- forced by a conical tubercule on either side of the rostrum. Whether this pair of tubercules replace the maxillae or not is uncertain. These appendages were not ob- served in the specimen under consideration, but the minute palps to which they are reduced were doubtfully traced in the next older specimen mesad from the lateral tuber- cules. The abdominal appendages are uniramous as before. The length of"/?" was mm. The "head" measured mm. long by mm. wide, the thorax was 120 mm. long, the abdomen 8 mm. long. The third specimen (C] differed from " B " in the still more inflated " head " and in the replacement of the maxillipeds by a pair of tubercules, so that the ventro-anterior face of the " head " now presented five tubercules, one median and four paired. The rostrum of this stage pointed in a line with the axis of the " head " and its tip together with the tips of the anter
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
