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DESCRIPTIONS OF THIRTY-ONE GASTROPODA AND ONE 

 SCAPIIOPOD FROM THE PERSIAN GULF AND GULF OF 

 OMAN, DREDGED BY MR. F. W. TOWNSEND, 1902-1904. 



By J. Cosmo Melvill, M.xi., F.L.S. 



Read 9th March, 1906. 



PLATES VII AND YIII. 



Tkk abyssal forms of molluscan life obtained beyond the 100 fathom 

 limit iu the Gulf of Oman seem almost inexhaustible, but the following- 

 descriptions well-nigh complete the series received up to the date 

 of writing these lines, excepting indeed so far as the Pelecypoda are 

 concerned. All of these, however, have at last been worked out, and 

 a catalogue is in course of compilation by myself and Mr. 11. Standen, 

 and this we ho[)e to publisli without much further delay — a delay, 

 I might add, that has been, from various causes, hitherto inevitable. 



Of the minute forms of Gastropoda in these seas, many are 

 exceedingly rare and local, others abound in countless numbers. 

 Another haul of the dredge from the prolific stations, lat. 24° 58' N., 

 long. 56° 54' E., at 156 fathoms, would no doubt have brought to 

 light some wonderful species that perhaps now we may never see. 

 Fragments, indeed, exist in the shell-sand of several unknown forms, 

 not. unfortunately, in a condition to be described. One such is, 

 perhaps, of the familj^ Solariidae, with flattened base, beautifuUj' finely 

 decussate surface, and curious deep and narrow umbilicus, but the 

 upper whorls are entirely broken away. Two or three Pleurotomidne 

 are in similar unfortunate condition, and a few others besides, the 

 families and genera of which can be but guessed at. 



I am informed by Mr. Townsend that the bringing up of this shell- 

 sand Avas mainly due to an absolute accident, the anchor of the 

 s.s. "Patrick Stewart" having dragged during the night, and stirred 

 up the bottom ooze to an unusual extent. 



When the abyssal and benthal life is better known, I should not 

 be surprised if it be found that the ' minutiora ' eclipse the larger 

 marine species numerically in the proportionate ratio of 3 : 1, or even 

 in a still greater degree. They are j ust as beautiful as —indeed, as a rule, 

 more delicately sculptured than — their better known congeners, and, 

 taken as a whole, do not seem to vary from their types to anything 

 like the same extent. When once, therefore, their ' t'acies ' has been 

 grasped, the task of discrimination and differentiation becomes easier 

 than might be thought to be the case by those who have not yet 

 studied them. 



When not otherwise stated, the locality for the following will be 

 the one just quoted above, viz., in the Gulf of Oman at 156 fathoms. 



