BLANFORD : LAND AND FRESH-WATER MOLLUSCA FROM SIAM. 283 
by Theobald as I. variabilis, var. pyramidalis (Journ. Asiat. Soc. 
Bengal, xxxiv, 1865, pt. 2, p. 274, pl. ix, fig. 7; see also Conch. 
Ind., pl. lxxv, fig. 8). The sculpture is different, as there are three 
nodose ridges round the whorls instead of two. A third allied form 
is Melania pagodula, Gould, from Tenasserim (made by H. Adams the 
type of a separate genus, Brotia, Proc. Zool. Soc., 1866, p. 150), but 
this has only a single spiny ridge round the whorls. Lastly, 
M. premordica, Tryon, from Pegu (Amer. Journ. Conch., ii, pt. 2, 
1866, p. 111, pl. x, fig. 3), resembles JL binodosa in shape, except 
that, judging from the figure, the aperture is narrower, and the ridges 
round the whorls are smooth, not nodose. 
A smaller specimen measures 38 mm. in length and 22mm. in 
breadth. 
[‘‘ Common in large rivers.” —W. M. D. | 
37. Patupomus Sramensis, sp. nov. Pl. VIII, Fig. 3. 
Testa ovato-conica, solidiuscula, epidermide olivacea vel fusco- 
olivacea induta, sub epidermide albida, fasciis latis spiralibus castaneis 
circumdata, infra suturam et ad basin distincte, versus peripheriam 
obsolete sulcata; spira conica, apice acuto, erosulo, sutura im- 
pressa; anfr. ad 6 convexi, ultimus 3 teste vix superans; apertura 
verticalis, ovata, superne angulata, intus trifasciata, fascia media 
ceteris angustiore; peristoma tenue, acutum, marginibus callo junctis, 
basali columellarique dilatatis, intus incrassatis. Operculum normale. 
Long. 11, diam. 7°5 mm.; ap. long. 7, lat. 5. 
Hab.—Siam, in valle superiore Menam fluminis. Type in the 
British Museum. 
I have no exact locality, but it is evident that this Paludomus, the 
first, so far as I can learn, that has been recorded from Siam, is from 
the upper Menam valley. 
A species referred by its describer, Commandant L. Morlet, to the 
Assamese 2. conica, Gray, has been obtained in Cambodia (Journ. de 
Conch , xxxvu, 1889, p. 146). 
The largest specimen I have seen is 12 by 8mm. The extreme 
apex is wanting in all the shells. 
The present species is most nearly allied to P. regulata, Bs., from 
Pegu, but that is considerably larger; the spiral sulcation is much 
stronger, the spire longer and the mouth shorter in proportion. There 
are only three chestnut spiral bands in P. Scamensis instead of four, 
and the second is narrower than the others, whereas in P. regulata 
there are usually four, all of equal breadth; but this is not a character 
of importance, for these coloured bands vary in different individuals. 
PELECYPODA. 
Family UNIONIDA. 
388. Unto Houser, Lea. 
39. Unio eravinus, Lea. 
40. Unio crispatus, Gld. 
[‘* Common in all rivers.’—W. M. D.] This applies to all three 
species. 
