SHELLS OF MEEGUI AND ITS ARCHIPELAGO. 



155 



pointed out as existing between Darwin's specimens and those 

 from Mergui, are due to difference in age. A specimen I dissected 

 was furnished with ovigerous lamella?. 



In figure 3 I have given a representation of the penis of this 

 species. \vnereas the probosciformed organ, except in certain 

 species of Scaljjellum, is very long, the present species has a 

 very thick and short penis, its tip being pointed and somewhat 

 hooked. Darwin does not describe the penis of this nor of any 

 other species of the genus. 



DESCRIPTION OF PLATE XIII. 



Fig. 1. Dichclaspis pellucida, Darwin, side view: X 14 diaui. 



Fig. 2. View of a part of the capitulum, to sliow A & B, the terga, & D, the 

 occludent segments of the scuta, and a, b, c, the angle the occludent 

 segment of the scutum forms with the handle of the battle-axe-shaped 

 tergum : X 30 diaui . 



Fig. 3. Representation of the penis : X 30 diam. 



List of the Shells of Mergui and its Archipelago, collected for 

 the Trustees of the Indian Museum, Calcutta, by Dr. John 

 Anderson, F.R.S., Superintendent of the Museum. By 

 Prof. Edtjaed von Masters, M.D., C.M.Z.S., of the 

 University of Berlin. (Communicated by Dr. John 

 Andekson, F.K.S., E.L.S.) 



[Read 17th June, 1886.] 

 (Plates XIV.-XVI.) 

 Inteoditctoby Remarks. 



The following is a list of the species of Mollusca collected by 

 Dr. John Anderson at Mergui and some of the islands of the 

 Tenasserim coast. The species have been determined chiefly by 

 comparison with the shells in the Zoological Museum of the Uni- 

 versity of Berlin, and by consulting the leading illustrative vrorks 

 of this department of science, the figures of which are here cited, 

 so far as they have been compared with the objects themselves, and 

 may help to secure the determination. Concerning the land and 

 freshwater Mollusca, I have derived very valuable information 

 from Hanley and Theobald's ' Conchologia Indica,' and from 

 Gr. Nevill's ' Hand-list of the Mollusca of the Indian Museum,' 

 vols. i. (1878) and ii. (1884) ; also from the paper by A. Grould in 



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