105 



DESCRIPTION OF A NEW SPECIES OF OPISTEOSTOMA 

 FROM BORNEO. 



By Edgar A. Smith, I.S.O. 



Read llth March, 1904. 



Altogether, including that about to be described, twenty-one 

 species of Opisthostoma are now known from Borneo. A list of fifteen 

 was published in the Annals and Magazine of Natural History for 

 1894, vol. xiv, pp. 2(59-273. Since that date the following species 

 have been described, namely, 0. Linterce, Sowb.,^ concinnum and 

 simplex, Fulton,^ Sarawacense {= Cookei, Smith) and Tiesenhauseni of 

 Gredler,^ and figures of five known species, hitherto unfigured, have 

 been given in the Proc. Zool. Soc, 1895, pi. iv, figs. 19-23. 



Opisthostoma Beddomei. 



Testa minima, angustissime perforata, rufescens, dextrorsa, pyra- 

 midalis ; anfractus 6 convexi, laraellis tenuissimis, subremotis, obliquis, 

 in medio undulatis, ornati, supremi 1-2 laeves, saturate rufescentes, 

 ultimus infra carino-cristatus, lamellis confertis instructus, antice 

 solutus, retrorsus, et sursum contortus ; apertura subcircularis, intus 

 pallide rufescens; peristoma duplex, albidum, margine interno tubae- 

 formi, expanse, externo aliquanto angusto, dextrorsum versus spiram 

 interrupto. Long. 1-75, diam. max. 2*25 mm.; apertura cum perist. 

 1 m. lata. 



Hab. — Bidi Mountains, 20 miles from Sarawak. 



This little species was collected by Mr. Sydney Beddome, after 

 whom I have much pleasure in naming it. The keel-like crest upon 

 the lower part of the body-whorl commences where the whorl is 

 constricted and its irregular contortion commences. The oblique 

 lamellae are excessively slender, like the finest threads, and slightly 

 wavy at the periphery. There are about eighteen upon the penulti- 

 mate whorl. The outer margin of the peristome is rather narrow, not 

 expanded like the inner edge, and interrupted on the right side, or 

 that towards the spire, as is the case also in some other species. 



1 Ann. & Mai?. Nat. Hist., vol. xvii (1896), p. 94. 



2 Op. cit., vol. viii (1901), p. 242. 



3 Nachrichtsb. deutsch. mal. Gesell., 1902, p. 57. 



