Larval development of two hippolytid shrimps, Heptacarpus geniculatus and H. pandaloides, which are very common in the weed beds in the vicinity of the Miyazima Aquarium, is dealt herewith. Under laboratory conditions are observed 9 zoeal, 1 megalopa and 1 young stage in the former and 7 zoeal, 1 megalopa and 1 young stage in the latter. H. pandaloides is the first species in this genus having 7 zoeal stages. Apart from the number of zoeal stages, these two species morphologically resemble each other, especially in the early zoeal stages. The characters distinguishing them from each other and from the other two known species, H. futilirostris and H. rectirostris, are shown in Table 4. The present results on H. geniculatus are rather different from the former information given by KURATA (1968b) and the differences are listed in Table 3 and briefly discussed.
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