530 Mr. H. B. Preston on MoUusca from 



base of sliell very indistinctly spirally striate ; perforation 

 very narrow ; columella triangularly outwardly expanded, 

 descending very obliquely ; labrum simple ; aperture broadly 

 and obliquely lunate. 



Alt. 11, diam. maj. 16, diam. min. 14 mm. 



Aperture: alt. 6, diam. 7 mm. 



Hah. Shimbi Hills, British East Africa, 



Allied to M. pynimidea, v. Mart., but with more exserted 

 spire, narrower and higher aperture, and finer transverse 

 sculpture than has that species. 



Martensia monozonata, sp. n. (Fig. 11.) 



Shell perforate, turbinately depressedly discoidal, thin, pale 

 yellowish flesh-colour, painted with a super-sutural band of 

 reddish purple, which appears as a super-peripheral band on 

 the last whorl, ornamented below the periphery with radiate 

 interrupted streaks of cream-colour ; whorls 5^, the last 

 carinate at the periphery, sculptured with very fine, closely 

 set, silky stiise; base of shell shining, very finely spirally 

 striate ; perforation very narrow ; columella descending 

 obliquely ; labrum acute ; aperture broadly sublunate. 



Alt. 7, diam, maj. 12*25, diam. min. 10'5 mm. 



Aperture : alt. 5, diam. 6 mm. 



Ilab. Shimbi Hills, Biitish East Africa. 



3fartensia (?) shimbiense, sp. n. (Fig. 12.) 



Shell broadly conoidal, thin, perforate, pale brown ; whorls 

 5^, the earlier whorls finely spirally sculptured, the later 

 sculptured with fine, very oblique, closely set, transverse striae, 

 the last whorl strongly carinate at the periphery ; base of 

 shell closely spirally striate; suture impressed, margined 

 above with a narrow ridge-like formation ; umbilicus mode- 

 rately narrow, very deep, partly concealed by the expansion 

 o£ the columella ; columella obtusely angled ; labrum acute ; 

 aperture broadly sublunate. 



Alt. 7*5, diam. maj. 10'5, diam. min. 9*5 mm. 



Aperture: alt. 4, diam. 4*25 mm. 



Lab. Shimbi Hills, British East Africa. 



Owing to the spirally sculptured apical whorls I am in 

 much doubt whether this species should rightly be placed iu 

 the section Martensia. 



Thapsia exasperata, sp. n. (Fig. 13.) 



Shell depressed, suborbicular, rimate, thin, horny, polished, 

 fulvous; whorls 4, marked with lines of growth; sutures 



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