MKLVILL : NEW MOLLUSCA FKOM THE PERSIAN GULF, ETC. 75 



The minutost luollusk yet discovered in the Persian Gulf region, 

 but, nevertheless, beautiful in form, being four to five-whorled, scalato- 

 gradate, longitudinally ribbed, ribs numbering about 12 on the body- 

 whorl, the interstices being smooth. The lip is angled above, nearly 

 straight otherwise, columella slightly excavate. But three or four 

 examples have so far occurred, but so tiny an organism can easily 

 be overlooked. 



Odostomia (Pyrgulina) thelxinoa,^ n.sp. PL VII, Fig. 14. 



0. {Pyrgulina) testa perminuta, angusta, gradatula, cylindrica, alba, 

 nitida, anfractibus 6-7, quorum duo apicales heterostrophi, vitrei, 

 globulosi, cfeteris apud suturas multum impressis, undique longitudi- 

 naliter costulatis, costulis fere rectis, delicatis, interstitiis sub lente 

 spiraliter arete striatis, apertura oblique ovata, labro pauUum effuso, 

 continuo, columella uniplicata. Long. 2, lat. "75 mm. 



This and the preceding Pyrgulina occurred almost equally rarely. 

 Their extremely small size, and, in the case of P. thelxinoa, its neatly 

 turreted or gradate whorls, will serve to distinguish them from their 

 allies. 



Odostomia (Miralda) ima,'^ n sp. PI. VII, Fig. 15. 



M. testa ovato-fasiforrai, corapressa, solidula, albida, anfractibus 6, 

 quorum 2 apicales laeves, heterostrophi, caeteris apud suturas bene 

 impressis, subcanaliculatis, superne apud medium anfractuum costatis, 

 trinis gemmularum ordinibus decoratis, costulis infra evauidis, sed, 

 penultimo et antepenultimo anfractibus una, ultimo multis ad basiiu 

 liris fortibus spiraliter accinctis, interstitiis sulculosis, apertura ovata, 

 labro extus crasso, paullum elfuso, columella uniplicata. Long. 2-5, 

 lat. 1. 



A chai-ming little species, nearly allied to M. diadema, A. Ad., from 

 Japan, and which has been also reported from Indian seas. It is more 

 compact, and stouter proportionately than either this or the allied 

 M. gemma, A. Ad., the disposition of gemmuled riblets on the upper 

 portion of the whorls, and spiral liroe on the lower, being identical. 

 I would also take this opportunity of stating that two allied species 

 from the Persian Gulf, described in 1903 by Mr. Standen and myself 

 as Actfeo'pyramis Icstitia and brevioula,'^ would be better located in the 

 genus Miralda. 



COLUMBELLA (iSeMINELLA) COMISTEA,* U.Sp. PI. VII, Fig. 16. 



C. testa minuta, obesa, utrint^ue attenuata, solida, Isevi, pallide 

 straminea, anfractibus 6, quorum 3 apicales vitrei, laeves, caeteris 

 undique longitudinaliter costulatis, aliter Irevissimis, ultimo pyriformi, 

 ad basim maxime attenuato, et spiraliter lirato-sulcata, costulis 

 dorsaliter inferne evauidis, apertura augustissima, labro incrassato, 

 nitido, arcuato, columella sinuata, ad basim attenuata, producta. 

 Long. 3, lat. 1mm., sp. maj. 



^ 6fA^ii/oos, ' charming.' 



- Imus, iu sense of 'abyssal.' 



3 Ann. & Mag. Nat. Hist., vol. xii (1903), p. 305, pi xxii, figs. 3, 4. 



* KOjUMTTfos, ' brought forward.' 



VOL. VII.— JUNE, 190(1. 6 



