302 LAND AND FRESHWATER 



Original description : — " Testa imperforata, r/loboso-conoidea, 

 tenui, striatula, nitidula, fusco-cornea, transluceiite, spira truncato- 

 conica, sutura impressa, aplce obtusissimo ; anfractibus 4 convexis, 

 ultimo globoso, antice sensim descendeiite ; apertura lunato-rotundata, 

 obliqun, peristomate acuta, margine dextro arcuato, collari acuto, 

 vertieali, cum basalt angulum fere rectum efformantes. 



" Long. 1|, diam. 1 mill. 



"Habitat ad Matelle. 



" Allied to H. orcula, B., of North-Eastern India, but smaller, 

 destitute of the peculiar sculpture of that species, and distin- 

 guished by its very obtuse apex and by the formation of the 

 columellar lip. It was found by Mr. F. Layard on the bark of an 

 orano^e-tree near his house at Matelle." 



Size of specimen (figs. 1 a, I b), Binoya Estate, Watawala, 

 Ceylon : major diam. 1-1, total length 1'53 mm. 



Some years ago I received from Mr. O. Collett, a number of 

 minute shells of three or four species taken upon the bark of 

 Mango trees during the rains, on the Binoya Estate, Watawala, 

 Ceylon, among them a species referable to this sub2;enus. It is 

 (luite of the type of lignicola and orcella figured by Stoliczka, but 

 it ia smaller tlian lignicola, has a greater number of whorls and is 

 more attenuate than orcella, while the trans\-erse striae of the 

 cuticle appear to be more regular. To throw light on the radula 

 I soaked some of them but failed to find one. I therefore 

 solicited Mr. Collett to collect some more, and have lately received 

 a number well preserved in formaUn, and am now enabled to 

 give the description of the jaw and radula of this interesting 

 subgenus. 



The foot of the animal is short, but it is too small to see any 

 details of its anatomy ; as Stoliczka says of P. orcella, the tentacles 

 cannot be made oiit. However, when the minute animal is 

 pressed out between covering-glasses, the eyes are conspicuous, 

 connected with a short dark streak representing the retractor 

 muscle. In life they probably merely reach the surface of the 

 integument. 



The radula (fig. 1 c) is exceedingly small, it has the formula 



8 . 6 . J .6.8 

 14 . 1 . 14. 



The centre tooth is smaller than those on either side, it is 

 tricuspid, the main point long, those on the side basal and wide 

 apart. The admedian teeth are also tricuspid with indication on 

 the 4'th and 5th of two cusps on the outer side. The laterals are 

 on lono- narrow plates, with four teeth alternately long and short. 

 The jaw (tig. 1 d), of which I only detected one, out of some five 

 specimens examined, is composed of about eighteen vertical plates, 

 not overlapping each other, each plate being separated by a very 

 narrow clear space. The cutting-edge is sharply defined. Under 

 the highest power it seemed apparent that these plates divided at 

 the ba°e and merged gradually into muscular tissue. 



