270 Mr. W. H. Benson on the genus Cyclostoma, 



viter ascendente, basi rotundato ; apertura ampla, vix obliqua, 

 leviter sursum spectante, subcirculari, fauce castanea, margine 

 rufo; peristomate duplicate, teuui, interno continuo, subito ex- 

 panse, exterao plane dilatato, praecipue ad partem columellarem, 

 vix reflexiusculo. 



Axis 23, diam. anfr. penult. 10, diam. apert. extern. 9, alt. apert. 7\ 

 mill. 



Hab. in Insula Borneo. 



In form much resembling C. altum of the Philippines, but 

 shorter and more rapidly tapering from the base to the summit, 

 dijffering also in tenuity, in the pale apex^ the absence of a funi- 

 culate keel at the base, the more convex whorls, and the more 

 coarsely striate ultimate volution. The penultimate whorl is not 

 broader than the last, as it is in C. altum ; at the same place 

 where the channel occurs on the inner lip in that shell there ap- 

 pears a very slight indentation. The summit and succeeding 

 whorl are white, as in C. Guildingianum, Pfeiffer. Two slightly 

 impressed lines traverse the last whorl spirally in the only spe- 

 cimen received through Dr. Bacon. They appear to be accidental, 

 and have therefore been omitted in the specific description. 



4. Cyclostoma quadrifilosum, nobis, n. s. 



Testa umbilicata, globoso-turbinata, sub epidermide hispida, et crebro 

 oblique lamellata, nitida, spiraliter 4-lirata, interstitiis striis minu- 

 tissimis spiralibus, alias obliquas decussantibus, munitis, castanea, 

 superne strigis pallidis distantibus ornata ; sutura impressa ; spira 

 conica acutiuscula ; anfractibus 5 convexis, ultimo liris 4 Hliformi- 

 bus instructo, prima supera, secunda ad periphseriam, tertia infe- 

 riori, quarta laasali ; umbilico angusto pervio ; apertura vix obliqua, 

 subcirculari, fauce castanea; peristomate duplicate, interiori ad 

 dextram recto, vix porrecto, ad sinistram expanso, sinuato, intus 

 leviter incrassato, albido, exteriori expansiusculo, nigrescente, an- 

 tice superne prorsum arcuato. 



Diam. major 6, minor 5, axis 5 mill. 



Hab. in Insula Borneo. 



The fourth filiform carina, which is present in both specimens 

 received (the other three being situated as in C Z-liratum, Pfr.), 

 the lamelliform epidermis, the spiral striae, the duplication of the 

 peristome, and the other characters of the aperture, seem to jus- 

 tify the distinction of this species from C. S-liratum, which in- 

 habits the same island, but which I only know from Pfeiffer's 

 description. C. Ai-filosum is a little smaller than that species. 

 The outer lip is separated from the internal peristome by a slight 

 sulcus. The two upper threads are continued on the penulti- 

 mate whorl, as in S-liratum. 



