1871.] F. Stoliczka — Notes on Terrestrial Mollusca. 223 



is thin and extends directly backwards, while the inner proceeds 

 obliquely across the lip, meeting a thin longitudinal rib, which runs 

 on the inner side of the largest lamina, so as to include a kind of a 

 triangular space. In this space there projects from the basal side of 

 the whorl a large oblique transverse lamina, accompanied on either 

 side by a thin longitudinal rib. Two thin ribs are situated on the 

 upper side of the whorl between the suture and the peripherical 

 keel. The median rib which originates near the edge of the inner 

 lip of the aperture extends only for a short distance internally. 

 The plication, as above described, was observed to be constant 

 in 8 specimens of various sizes. 



Judging from the description of Pfeiffer's H. revolnta (Mon. Hel., 

 v, 416) I can hardly think that the shell referred to can be distinct 

 from cyclaspis. I have specimens of this last which perfectly agree 

 with the measurements given by Pfeiffer of his revoluta, and said 

 to be from the Andamans. I never received cyclaspis amongst 

 many thousands of shells from those islands, and I doubt its occur- 

 rence there quite as much as that of P. achatina, recorded by Tryon, 

 (comp. Proc. Asiat. Soc, March, 1870, p. 88). The shell fauna 

 of the Andamans and Nicobars shews considerable relations to that 

 of Arracan, but barely any to that of the limestone hills about 

 Moulmein. The latter is, as already stated, quite peculiar, and 

 very distinct from the fauna of the adjoining low lands, and even 

 from that of the neighbouring sandstone hills. 



P. cyclaspis is found sparingly on all the limestone hills about 

 Moulmein. The animal is very shy, usually living in crevices and 

 holes, and closely adhering to the rock even when moving about. 

 It is uniform dark grey or blackish with a pink tinge, paler on 

 the pedicles and tentacles, the latter being very small and situated 

 quite at the base of the mouth ; the warts of the body are black 

 and rather large. 



•o' 



Genus. Trachia, Albers. 



(See pi. xvi, figs. 1 — 3, and the accompanying explanation.) 

 This genus was proposed by Albers for JET. asperella, Pfr., as type. 

 It is characterised by a planorboid shape, moderately thin semi-trans- 

 parent structure of the shell, covered with a setaceous cuticle, by 



