170 | MR. H. F. BLANFORD'S REVIEW OF 
from Peradinia, near Kandy, the upper whorls are in certain of the specimens somewhat 
exserted, but only to a slight degree. In the more elongate forms the slight flattening 
and angulation of the upper part of the whorls which characterize the more globose 
specimens tend to become obsolete. ! 
Coloured specimens, which are almost always young shells, have sometimes two, some- 
times three bands. 
The operculum of this species is characterized by its more pyriform shape than that of 
Philopotamis sulcata, and by the nucleus being further from the margin. The position 
of the latter is somewhat variable (see fig. 12 a, b). 
Paludomus olivaceus, Reeve, from Sumatra, bears much resemblance to this species ; 
but, in the absence of its operculum, no safe conclusion can be drawn. 
PHILOPOTAMIS NIGRICANS, Reeve. (Pl. XXVII. figs. 3 a—e, 15 a, ù.) 
Shell of type-form, thick, elevately conical (apical whorls almost invariably eroded), 
ornamented with close-set granular strive, those near the suture more developed than 
the rest. Colour of epidermis dark citrine to black. The shell painted with numerous 
wavy brown bands, generally visible only in the interior, and sometimes obsolete near the 
aperture. Spire, when perfect, acutely conical; whorls about six, rarely more than three 
remaining in eroded shells, flattened, with shallow sutures. Last whorl more or less 
angulate at the periphery, obliquely flattened beneath. Aperture obliquely ovate, 
pointed above. Peristome white or greyish white, callous: outer lip sharp, even: 
columella slightly arcuated anteriorly. Operculum paucispiral: nucleus rather large, 
transversely central, and at from th to 3ths of the height. 
Var. «. (The only specimens found, not fully grown.) Shell in form as above, uneroded, 
smooth, with one or two strong stris only near the suture. Epidermis transparent, 
citrine, with the markings of the shell distinctly visible through it. 
.? Var. B. Form of shell as above, but more elongate. Shell smooth, colourless or with 
the bands broken up into a series of square dots. Last whorl elongate, the angulation 
nearly or quite obsolete (Pl. XXVII. fig. 3 e). 
This species is more nearly allied to Melania, both in form and in the structure of the 
operculum, than any of its allies. From P. decussata, the only congener to which it 
bears any near resemblance, it is distinguished by its more conical form, the angularity 
of the last whorl, and the character of the marking, as well as, in the majority of speci- 
mens, by the granular surface, which, so far as I have seen, is peculiar to this species. 
The type-forms and thé var. «. were collected by myself in large numbers (associated 
with Tanalia violacea) in some small mountain streams near Huckgalle, at an elevation 
of 5000 feet. "With regard to var. 8, I am in some doubt whether it really belongs to this 
species, notwithstanding that var. a, and a single colourless specimen of the normal form 
given me by Mr. Cuming, seem to link it with the type. The only specimens I have 
seen were in Mr. Cuming's collection, where they were erroneously referred to Paludomus 
palustris, and none of the specimens contained opereula. In the absence, however, of 
any adverse evidence, I provisionally regard this as a variety of P. nigricans. 
