Burmese Species of Assiminea. 385 



rans, subverticalis, supra acute angulata ; peristoma rectum, 

 margine externo tenui, columellari incrassato expanse. 

 Operculum corneum, tenue, radiatim striatum, distincte paucispirale. 

 Long. 5|, diam. 4, apert. long. 3^, lat. 2| millim. 



Hab. Mud between tide-marks near Dalhousie, in the Ira- 

 waddy Delta. 



Animal scarlet; proboscis bilobed, with a black spot above in 

 the centre of each lobe. The ends of the proboscis are applied 

 in walking. Tentacles and eyes as usual in Assiminea, The 

 animal closely resembled that of A. marginata, Leith, in which, 

 however, the black spots on the proboscis are wanting. The 

 shell is perhaps, on the whole, more nearly allied to A. rotunda, 

 Fairbank ; but that species has no spiral lines below the suture, 

 and the animal is diflferently coloured. A. rubella differs from 

 A. pinguisj Von Martens, in being more globose, in having a 

 double instead of a single impressed line below the suture, and 

 in the colour of the animal. 



I found Assiminea rubella very abundant crawling upon the 

 mud between tide-marks, just above the port of Dalhousie in 

 the Bassein river, one of the many mouths of the Irawaddy, but 

 which, like several of the mouths of the Ganges, is for many 

 months of the year an arm of the sea rather than a river, as it 

 receives scarcely any fresh water except in the rainy season. 

 The whole molluscan fauna of this portion of the Irawaddy delta 

 is peculiar and very interesting, comprising a new genus of 

 Rissoidse, species of Tedura, Martesia, Teredo j and other marine 

 forms, with iluviatile or estuarine types such as Neritina, Cy- 

 rena, and Scaphula, With the Assiminea a species of Amphibola 

 occurred in abundance. A small form, apparently of the same 

 species, occurs with the Assiminea of Bombay. I have described 

 the molluscan fauna of the Irawaddy delta in a paper which will 

 be published in the 'Journal of the Asiatic Society of Bengal.' 



Within the last few days I have received from Mr. Damon 

 specimens of an Assiminea from Borneo, which appear to belong 

 to the present species. In one specimen there is only a single 

 impressed line below the sutures ; but in another there are two, 

 which are even more strongly marked than in Burmese specimens. 



The only other known species of Assiminea inhabiting India 

 or Burma, as already observed, is A. Francisci, Gray. This 

 abounds on the mud of the Hoogly and of various tidal creeks 

 and canals around Calcutta ; and a variety, differing in nothing 

 except its rather darker and occasionally reddish colour, is found 

 at Molmain in Burma. Specimens were found there, I think, 

 by Mr. Theobald ; and some were brought to me, amongst other 

 shells, by a collector whom I sent to Molmain. 



As regards the habits of Assiminea, I can, to a very great ex- 

 tent, confirm the remarks of Dr. von Martens. It is essentially 



