1855.] Chusan Shells. 131 



flexo, nigrescente ; labio crassissimo ; operculo testaceo ; umbilico 

 evanido ; apice obtuso. 



This shell appertains to the group of small Paludince which Gray- 

 has separated under the designation of Bithinia, to which belong 

 the English P. impura, the Indian species cerameopoma and pulchella, 

 (nobis), goniostoma (Hutton) and one or two other species, inhabit- 

 ing the rivers and pools of the gangetic plains, which as yet are 

 undescribed. The present species is remarkable for the thickening 

 of the inner lip in the part where it adheres to the penultimate 

 whorl. 



" Found in the canals in great numbers, attached to aquatic plants, 

 stones, piles, &c." 



Paltjdina (Bithinia) steiatula, Benson. 



Testa ovato-acuta, cornea, polita ; spira elongata ; anfractibua 

 quinque convexiusculis, liris pluribus, interdum inconspicuis, circum- 

 datis, suturis depressiusculis ; apice obtusato. Peristomate reflexo, 

 nigrescente, undato ; umbilico evanido ; operculo calcareo. 



This form is singular among the Bithinia on account of the ridges 

 on the whorls. All the other known species, including those above 

 named, viz. parvula of the West Indies, rudis and rubens of Dal- 

 m&tm, fluminensis of Hungary, inflata of the Ionian Islands, and a 

 small Sicilian species which stands in my collection without a name, 

 being deficient in sculpture. The number and degree of prominence 

 of the ridges vary much, and they diminish in prominence in propor- 

 tion to their paucity. 



" Less common than P. longicornis, but found in the same localities. 

 The animals and their habits are similar." 



Melania cancellata, Benson. 



Testa elongato-turrita, olivacea solidiuscula ; anfractibus novem 

 convexiusculis, omnibus costulis frequentibus, ultimoque fasciis tribus 

 elevatis basalibus munitis ; costulis liris plurimis cancellatis ; suturis 

 mediocriter excavatis ; apice eroso. 



Axis 1.0 poll, vei paulo plus. 



This little species is nearly allied to the gigantic, M. variabilis, 

 nobis, of Bengal, and like it, has the sinuated aperture, which indi- 

 cates the approach of the genus to the neighbouring type : Mela- 



