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No. VII.— REPOUT ON THE MARINE MOLLUSOA OBTAINED BY 

 Mr. J. STANLEY GARDINER, F.R.S., AMONG THE ISLANDS OE 

 THE INDIAN OCEAN IN 1905. 



By James Cosmo Melvill, II.A., D.Sc, F.L.S. 



(Plate 5.) 



Read 1st April, 1909. 



The Gastropoda and Pelecypoda collected in 1905 during the cruise of H.M.S. Sealark 

 consist in great measure of sjiecies widely dispersed over the immense area of the Indo- 

 Pacific region. The annexed, table has been purposely drawn up so that the individual 

 distribution, so far as is at present known, might be discerned at a glance, by a wide 

 range of localities being given for comparison, extending from Natal and the Cape on 

 the south-west to Japan on the north-eastern confines of that region. No opportunity 

 seems to have been missed by the energetic explorers attached to the Expedition, 

 but, apparently, the rough coral-ground and Lithothamnia- or Halimeda-rvMbXe, which 

 so often characterize the quality of the various soundings, are not conducive to the 

 free growth of the more delicate and smaller molluscan organisms — e. g., the Opistho- 

 branchiata and members of the Rissoidse or Pyramidellidse. Nor is the large and 

 important family Pleurotomidaj well represented, which, indeed, contributes so large 

 a proportion of the species obtained further north in the same ocean — e. g., by the 

 dredging-results of H.M.S. ' Inrestigator ' in the Bay of Bengal and elsewhere and 

 those in the Persian Gulf and North Arabian Sea particularly associated Avith the 

 name of Mr. F. W. Townsend. 



But however this may be, some remarkably select and interesting forms are here 

 enumerated, notably in the genei-a Solariella, Mitra, Cyprcea, LambicUum, and Terebra. 

 The genus Turbo likewise, with the Trochidse, is remarkable for the number of specimens, 

 as well as species, obtained. The recurrence of the genus Struthiolaria at the Seychelles 

 is also very noteworthy, as it has hitherto been believed to be confined to New Zealand. 



Amongst the Pelecypoda, Cardium and Fecten are both especially numerically strong 

 in representatives, while, contrary to usual custom, but few Tellinidae occur. 



The Scaphopoda are but three in number, two being additions to the genus Deiitalium. 



Altogether between 465 and 475 are named in the accompanying catalogue, and of 

 these, fifteen are characterized as new to science. 



The classification adopted is mainly that of Dr. P. Pelseneer, as proposed in his 

 'Introduction a Tetude des MoUusques,' with modifications to some extent borrowed 



SECOND SERIES.—ZOOLOGT, VOL. XIII. 9 



