ig2i.] B. Prashad ; Sumatran Molluscs. 469 



teriorly and narrowly rounded anteriorly, its main axis forming 

 an acute angle with that of the shell ; the outer lip with a well 

 defined internal ridge but sharp at the edge ; columellar tooth 

 obsolete, parietal of moderate size. Periostracum thin, bright 

 chestnut, streaked on the body-whorl with irregular deep brown 

 longitudinal stripes ; longitudinal sculpture consisting of irregularly 

 sinuate Hnes; the whole surface covered with minute tubercular 

 spiral lines, which become gradually less well developed from 

 behind forwards but never disappear altogether. 



The single specimen of this shell, collected by Mr. den Doop 

 in a mangrove-swamp at Batang Kwis (Serdang), measures 36'7 

 mm. by i8'2 mm., the mouth measures 267 mm. by 8'5 mm. 



The shell resembles .4. morchi. Menke, in outline and colour, 

 but it is evidently thinner and has the suture less impressed and 

 the parietal tooth much better developed. The mouth also is 

 more elongate and the lip much thinner. The species is interesting 

 as providing a link between the large thick-shelled forms of the 

 genus and the small thin-shelled species. 



Family Limnaeidae. 



Genus Limnaea, Lamarck. 



Two species of this genus, L. javanica (Mouss.) and the highly 

 p-eculiar L. brevispira, v. Martens, have been recorded from Sum- 

 atra,' but only the former is represented in the present collection. 



Limnaea javanica (Mouss.). 



1S4Q. Liiniiaeiis siicciiieiis var. jnvaiiica, Moussoii, Moll. Java, pp. 42, 



4,^, pi. V. fig. I. 

 1897. Limnaea javanica, v. Marrens. op. cit., p. 3. 

 1899. Limnaea javanica, Dautzenberg, Mem. Soc. Roy. Malacol. Belgi- 



qiie, XXIV, p. 8. 

 1912-1913. Limnaea javanica, var., Schepmann, Pi-oc. Malacol. Soc. 



London, X, pp. 2},^, 236. 



Mousson described this species as a variety of Limnaea suc- 

 cinea, Desh., but as v. Martens and others have shown, the species, 

 though allied to it, is quite distinct. It ma}' also be noted here 

 that L. SHCcinea, Desh. is only a synonym or at the most a form 

 of L. lilt cola, Lam. 



In the Sumatran collection this variable species is represented 

 by a large series of specimens from various localities. None of 

 the specimens belong to the typical form, but specimens of the 

 following six forms described by v. Martens are present : — intumus- 

 cens, S'ubtercs, angustior, porvccta, costulata and turgidnla. Besides 

 the above there are a few individuals which it is not possible to 

 assign to varietal rank. 



' Prof. Max Weber collected especially in the western south half of Sumatra. 

 These regions are geologically more related to Java, whereas the north half of 

 Sumatra generally has more relations to the continent of .Asia, [den DoopJ. 



