450 Mr. W.T. Blanford on the Classification of 
to the tubes in other genera of the Cyclophoride. There can 
be no doubt that the “wing” in Pterocyclos is a rudimentary 
tube, although no portion of the animal has been observed to 
correspond with it. 
The species of this genus may well be distinguished into two 
sections. 
1st. Those inhabiting the Indian peninsula and Ceylon, 
v1Z. :— 
P. rupestris, Bens. Bengal, Behar, Orissa. 
P. bilabiatus, Bens. Hills of South India (base). 
P. nanus, Bens. Nilgiri Hills. 
P. Cumingi*, Pfr. Ceylon. 
These are all characterized by their very convex opercula. 
2nd. The Burmese forms— 
P. parvus, Pearson. Assam and Arakant. 
P. pullatus, Bens. Pegu. 
iB ,n.sp. Thayet Myo, Pegu. 
Also, probably, P. cetra, Bens., from Molmain, and P. Albersi, 
Pfr., from the Khasi Hills. In these the operculum is nearly 
flat, while the wing of the peristome is much less developed 
than in the forms of the Indian peninsula. No species have as 
yet been obtained from the Himalaya. It is worthy of note 
that the Indian species with the least-convex operculum and 
smallest wing is the Nilgini P. nanus, Bens., thus affording an- 
* Tam doubtful whether P. Cingalensis, Bens., be more than a variety of 
P. Cumingi, Pfr. The duplication of the peristome is frequently a character 
depending upon the age of the shell, which, of course, may vary in speci- 
mens collected at different periods of the year. Moreover, which of the 
Cingalese species is P. Troscheli, Bens.? Probably P. Cumingi or P. bifrons, 
Pfr., which may possibly be only varieties of one species. P. Troscheli was 
described from a drawing, at a time when the fauna of Ceylon was almost 
completely unknown. This has changed, and the land-Mollusca of Ceylon 
are now far better known, and have been much more largely collected than 
those of many parts of India; and it is very improbable that the species 
has been overlooked. Descriptions of species from drawings, unless those 
drawings have been made by persons intimately acquainted with the critical 
distinctions of allied species, are never satisfactory ; and when, as in this 
case, three or four other species have been subsequently described from 
the same geographical area, differing from that first named and from each 
other in minute characters which would infallibly be overlooked by an 
ordinary observer, it is very improbable that all are really distinct, It is 
to be hoped that some of the numerous collectors of Ceylon shells may 
possess specimens of a Pterocyclos from Trincomalee, which would go far 
towards deciding the question. 
+ Specimens of a Pterocyclos which I found in Arakan, at Akyab, and 
of which a flatter variety occurred further south, near Tongoop, agree 
generally with the description of P. parvus. The operculum is plano- 
concave within (the central boss being very slightly prominent) and nearly 
flat without, with free lamellar edges to the whorls. 
es 
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