Species of Diplommatina, Opisthostoma, ce. 243 
termination; aperture circular; peristome thin, slightly 
expanded, margined by a moderately broad rim or flange. 
Alt. 23 millim.; diam. maj. 3 millim. 
Hab. Gomanton, N. Borneo. 
Compared with O. Lintere, Sowb., to which it bears a close 
superficial resemblance, the present species is slightly smaller, 
the whorls are narrower and increase less quickly, and the 
last half-whorl (free portion) is more angular. 
The coste on last whorl of concinnum form narrow, almost 
complete, tubes, whereas in Lintere the coste# extend across 
the whorl as in O. pulchellum. The deflection at the 
constriction is also greater in Lintere. 
Opisthostoma simplex, sp. n. 
Shell pyramidal, narrowly perforate, apical whorls reddish, 
lower whorls of a somewhat shining golden colour ; whorls 6, 
convex, slowly increasing, ornamented with close oblique 
costz ; aperture circular; peristome thin, slightly expanded, 
not free, right-hand margin touching the whorls, bordered at 
the inner margin with a narrow thin rim or flange which is 
expanded at the upper part. 
Alt. 12 millim.; diam. maj. 2 millim. 
flab. (Gomanton, N. Borneo. 
This form is nearest in its general characters to O. Austen, 
Smith, but can be readily distinguished from that species by 
its smaller size and different peristome, which in Austen? is 
rather thick and has practically no flange ; whereas in s¢mplex 
the peristome is thin and the flange produced, especially at 
its upper part. The aperture of O. Austent is somewhat 
angular, not circular as in O. simplex. 
Opisthostoma Smithi, sp. n. 
Shell pyramidal, narrowly perforate, red above, pale yellow 
below, ornamented with oblique coste, which are semitubular 
on lower portion of last half-whorl; whorls 7, angularly 
convex ; aperture circular; peristome free, slightly thickened 
and expanded, and margined by a moderately wide rim. 
Alt. 3 millim. ; diam. maj. 34 millim. 
Hab. Banguey Island, Borneo. 
This distinct new species is somewhat like O. Cooker, Smith, 
in form ; its sculpture is similar to that of O. Everett’, Smith, 
but not so prominently developed as in that species. 
Named in honour of Edgar A. Smith, Esq., Assistant- 
Keeper of Zoology at the British Museum. 
