. Annual report. 1st-12th, 1867-1878. Geology. FACKAKD.] ANATOMY OF NEBALIA. 439 larvse as antennal and shell glands, but which in the Malacostraca un- dergo a substantial reduction, we find in Xebalia the anterior pair as slender glandular tubes in the basal joint of the 2d antennae. This re- lation of this gland, which is absorbed in the course of the metamorphosis, but in the Malacostraca, however, is generally present as a simple or winding glandular passage, affirms further the near affinity of Xebalia to the Malacostraca stem. Of the complicated shell-gland no remains survive in the Mala
. Annual report. 1st-12th, 1867-1878. Geology. FACKAKD.] ANATOMY OF NEBALIA. 439 larvse as antennal and shell glands, but which in the Malacostraca un- dergo a substantial reduction, we find in Xebalia the anterior pair as slender glandular tubes in the basal joint of the 2d antennae. This re- lation of this gland, which is absorbed in the course of the metamorphosis, but in the Malacostraca, however, is generally present as a simple or winding glandular passage, affirms further the near affinity of Xebalia to the Malacostraca stem. Of the complicated shell-gland no remains survive in the Malacostraca. What we are accustomed to regard in the Decapoda as shell-glauds is nothing more than the anterior gland which belongs to the maxillary region, but opens externally on the basal joint of the 2d antenna?. But we can surely prove, after careful researches on living Malacostracan larvae, that the rudiments or survivors of this gland are situated on the sides of the inaxillre (kiefer). In the Stomapod larvre I think I have found such a survival in the shape of a simple, somewhat curved glandular tube; and also in this place the residuum of the shell-muscles are preserved. The shell or adductor muscles of Xebalia appear to be well developed, quite as in the shelled Phyllopods. On each side of the shell we observe, under the mandibles, somewhat dorsally, a large round impression with an upper and under somewhat curved row of muscle-facets. On the upper end of the group of mus- cles, however, on the inner side of the shell, is to be found a small gland- ular tube, which with a contracted neck extends to the region of the maxillse, and is surely nothing else than the survivor of the true shell- gland of the ; Our sections of the body of Nebalia bipes show that in their general features the digestive canal and appendages are much as Claus de- scribes for the Mediterranean species. We were unable to get good sections of the proventriculus or Icaumagen. Plate X
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