274 Land and Freshwater Shells from the Shan States. [No. 4, 



usually three, series of prominent tubercles, ranged in symmetrical spiral 

 order with four non -tubercular spiral keels on the last whorl towards the 

 month. The tubercles form oblique transverse ribs, but the ribs are 

 a subordinate feature to the spiral ornamentation. 2.00 X 0.75. 



4th. Pyramidalis. Ornamentation like the last var. but form very 

 squat, with rapidly increasing whorls. The shell is slightly ccerulescent, 

 with four dark brown stripes visible in the interior, corresponding with 

 the spiral keels outside. Columella slightly yellowish, apex but little 

 eroded. 1.90 X 0.85. 



Grotto in Nam-mah stream. 



2nd. JBaccifera. This var. is intermediate in its character between 

 vars. 2 and 3. Its whorls are ornamented with four or five rows of 

 beaded keels, the transverse ribbing being often well marked likewise. 

 Most of the specimens were dead shells. 1.90 X 0.75. 



It is noteworthy that the ordinary type of M. variabilis, or the huge 

 specimens of the race met with in the Arakan hills, are not represented 

 in the collection, though the abundance of calcareous rocks and calc tuff 

 would, primS facie, lead us to expect shells of similar, if not greater, 

 dimensions. Climate and a lower average temperature of the streams 

 in the Shan country may possibly explain the small size M. variabilis 

 there attains, since I have a Maulmein shell which measures 4.00 

 X 1.30, and Arakan specimens not rarely attain (decollated shells). 

 3.00 X 1-30. 



3. 1 Paludomus. 



A single specimen of a large paludomus, which I haA^e not 

 yet identified, occurred in the collection. 



Fam. PALUDINIDiE. 



4. 1 Paludina naticordes, n. s. 



Two marked varieties of this shell occur. A smooth one with one, 

 two or three filiform keels, and a strongly keeled var. with prominent, 

 rugose keels. The species is probably undescribed and may be thus 

 characterised. 



P. naticordes, Th. — Testa turbinata, sub-polita, solida, pallide flaves- 

 cente cornea ad peripheriam carina munita ; marginibus callo junctis, 

 callo columellari non raro valde incrassato, umbilicum obtegente. 



Varietas fasciata, fasciis cluabus castaneis ornatur, hac superperijdieri- 

 ali, ilia juxta suturam posita. Anfractu ultimo tertia notest a carina 



