342 LIEUT. -COL. H. H. GODWIN-AUSTEN ON [June 18, 



Rhtostoma, Benson. 

 I ^ 26. Rhiostoma CAVERN.E, n. so. (Plate XXXVI. figs. 1, la.) 



Shell dextral, discoid, rather solid, very widely and perspectively 

 nmbilicated ; sculpture smooth, with fine transverse lines of jirowth ; 

 colour pale umber-brown ; spire just raised above last whorl; ajiex 

 flat ; suture well impres-^ed ; whorls 4, well rounded, tlie last sepa- 

 rated from the others for a distance of 4 millim., the sutural tube lying 

 about midway, rather nearer to the aperture, it is short and recurved ; 

 aperture circular, oblique ; peristome double, inner simple, continuous, 

 the outer expanded on the exterior margin and into a very slight 

 wing at the sutural side. 



Size: maj. diam. 15-0, min. lO'o; alt. axis 3-2.5: diam. body- 

 whorl 60 millim. 



Operculum multispiral, shelly in front and slightly convex, double, 

 horny, polished, multispiral at inner side. 



Hab. Sarawak proper. 



The first specimens sent home by Mr. Everett were four in number, 

 obtained when making excavations in certain caves in the limestone 

 formation, and marked Cave A, The specific name is only given in 

 allusion to this work, not that the species habitually lives in such 

 places. These are somewhat larger than the one described and 

 figured, being in major diam. 19 milUm., minor diam. 14 millim. 



f\ ^ 27. Rhiostoma Gwendolens, n. sp. (Plate XXXVl. figs. 2, 



' ' 2a) 



Shell dextral, globosely discoid, solid, openly nmbilicated; sculpture 

 a thick finely striate epidermis ; colour dark umber-brown, with 

 transverse bands of a darker colour, towards the apes zigzag bars 

 are seen where this epidermis has come off; spire low; apex papilli- 

 form ; suture well impressed ; sutural tube 2 millim. in length, taper- 

 ing and directed forward ; whorls 4 j, rounded, the last separated 

 from the other whorls from the base of sutural tube; aperture 

 circular ; peristome double, the inner lip thin and continuous, the 

 outer expanded and reflected on the outer margin. 



Size: maj. diam. 1.5-25, min. 11-7.5; alt. axis 5-0; diam. body- 

 whorl 7'5 millim. 



Operculum thin, flat, smooth, multispiral, and shelly in front, 

 smooth and horny behind, with a central circular hole. 



Hab. Niah Hills {A. Everett). 



Only one specimen in the collection, which is quite distinct from 

 all other species of this genus from Borneo in its more closely round 

 and globose form. 



Af-ff^ 28. Rhiostoma hungerfordi, n. sp. 



Shell discoid, umbilicated ; colour rich dark madder-brown, crossed 

 with broad regular V-shaped markings for 4 whorls, where the varix 

 of an old aperture is seen ; in front of this the markings are less 

 dcTeloped ; spire perfectly flat ; apex papillate, scarcely raised above 

 the succeeding whorls ; suture well impressed, the tube small, adhering 



