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Show 456 MOLLUSCA OF THE ANDAMAN AND NICOBAR ISLANDS. [May 21, distinct transverse fine ribbing is seen, and on breaking a mature shell back to the same number of whorls as in so-called Sagdinella a precisely similar form of shell was presented. Moreover, this Pupina, at the commencement of the fifth whorl, contracts very considerably and the shell is perforate at this stage. On turning to the original description I see that Professor Morch described it from a single example, and I can quite understand his being misled by this peculiar young form, so very unlike the typical mature shell in Pupina. I note that in this white very thin.variety every gradation can be seen from shells quite glassy to others most distinctly ribbed. The drawing of Sagdinella clidrichseni given on plate ix. figs. 1,1 a, in m y ' Land and Freshwater Mollusca of India,' was made from the type specimen sent to m e from the Copenhagen Museum. HELICINA. Nevill gives many varieties and subvarieties of the species of this genus, particularly of H. andamanica and H. scrupulum; he records that the animal of H. andamanica from Mount Harriet, Port Blair, " is of a mottled dark grey colour, sparsely dotted with sand-like specks, base of the tentacles yellow," List of Genera and number of Species. HELICACEA. Genus. Maerochlamvs Rotula Macrochlamys? Microcystis Durgella Rhy sota Trochomorpboides .lanira and 6 varieties ,, -Opeas Vaeinulus Common. 1 "i i Y 5 1 Andaman. 10 "i 2 "i 4 5 2 1 6 2 4 1 Y o 1 2 1 1 51 Nicobar. % 1 3 1 1 3] 6 2 1 1 2 3 1 3 2 1 "i 3 Y 43 1 Total. 10 6 3 4 1 5 5 10 2 1 7 1 1 4 7 2 3 2 3 1 4 4 1 881 |