172 MR. H. F. BLANFORD'S REVIEW OF 



PALUDOMtis CHILINOIDES, Reeve. (PI. XXVII. figs. 4 a-/.) 



P. constrictus, Reeve ; P. phasianinus, Layard (not Reeve) ; P. lavis, Layard ; P. (Rivulma) Zeylanica, 

 Lea; P.fulguratus, Dohrn ; P. nasutus, Dohrn. 



Shell thick, ovate or ovate-conic, smooth (rarely having traces of spiral sulci on the 

 upper part of the whorls). Colour of epidermis citrine or citrine yellow. Shell orna- 

 mented with spiral bands of brown crow's-feet markings, which sometimes coalesce into 

 transverse zigzags (P.fuhjumtus), sometimes, but very rarely, into longitudinal (spiral) 

 bands. Spire always exserted, sometimes elevated. Whorls 5, all rounded, obliquely 

 flattened above; upper whorls more or less eroded; last whorl ventricose. Sutures 

 impressed. Aperture ovate, flattened on the columellar side, angulate above. Outer lip 

 sharp : inner lip callous, usually white, rarely citrine-tinted on the edge. Interior of 

 aperture lined with white callus in old shells. Operculum with small spiral nucleus, 

 about central on the longitudinal axis, at about Jrd of the transverse axis from the 

 sinistral margin. 



In the above description I have briefly indicated the chief points in which P. chili- 

 noides is variable. The most striking of these are the elevation of the spire and the 

 markings of the shell ; but the differences observable in the latter are not so great as to 

 lead to any doubt of the specific identity of the specimens in question. To illustrate the 

 variation of form I give a selected series, PI. XXVII. figs. 4 a-f, of which fig. 4 a is from 

 an unknown locality in Ceylon, figs. 4 6 and 4 c from Peradinia near Kandy, and the 

 remainder from a stream at Ballepane, on the Colombo and Kandy road. Prom these it 

 will be seen that, as in the case of Tanalia aculeate^ specimens from the same locality 

 vary somewhat in form, but in order to ascertain the full extent of variation a wider 

 selection is necessary. This series also exhibits a certain amount of variation in point of 

 size, but not to the full extent actually observed. I have not, indeed, met with any 

 much larger specimens, but smaller shells than fig. 4 a are occasionally to be met with, 

 though rare. 



I distinguish this species from P. Tanjoriensis chiefly by the smoothness of the upper 

 whorls, and by the inferior height and the obtuseness of the spire, which is generally 

 eroded. The whorls in all varieties of P. chilinoides are smooth ; and though sometimes 

 subangulate, owing to the flattening of the upper surface, they never have anything like 

 the sharp keel which distinguishes the apical whorls of most varieties of P. Tanjoriensis. 

 Moreover, P. chilinoides never exhibits that distinct margination of the sutures which is 

 almost invariable in the other species. I have never noticed more than five whorls in 

 P. chilinoides, while P. Tanjoriensis has sometimes as many as eight. Varieties occur 

 upon which it is difficult to pronounce satisfactorily, but the great majority of the speci- 

 mens are so well marked that I have little or no doubt of their specific distinctness. 



The range of P. chilinoides appears to be confined to the southern provinces of the 

 island at least I have met with no specimens among the shells received from the 

 northern plains. This species is found in streams of all sizes, generally on sand and mud, 

 and is frequent in small sluggish brooks as well as in those of more rapid flow. 



The animal is of a dark slate-colour, nearly black on the sides of the foot, muzzle, and 



