462 Mr. W. H. Benson’s Conchological Notices. 
PTEROCYCLOS BILABIATUS, Bens. 
In the first number of the Journal of the Asiatic Society of Calcutta 
(January, 1832,) I described under the name of Pterocyclos a genus 
allied to Cyclostoma, and remarkable on account of the outer lip of the 
shell being separated at its upper part from the body of the penultimate 
volution, outside of which it rises vertically, somewhat in the shape of 
a wing. 
Since my arrival in England I have satisfied myself by the inspection 
of Mr. G. B. Sowerby’s specimens, that his Cyclostoma bilabiatum is the 
same shell at a more advanced period of growth; when, in addition to 
the notch and over-hanging wing at the upper part of the aperture, the 
peristome becomes thickened and sinuated. Mr. Sowerby’s specimens 
were from Salem in the Madras Presidency ; mine were met with at 
Sicrigully, a pass between the hills and the River Ganges, in Bahar. 
I am indebted to Mr. Sowerby for a specimen of Cyclostoma Petiveria- 
num, Gray, and for the observation that it exhibits an approach to 
Pterocyclos in the crude formation of a wing at the upper part of the right 
lip. 
CycLosToma INVoLvuLus, Gray, MS. 
I found this beautiful species alive on the rocks of Sicrigully, and 
among loose brick rubbish and under felled timber, in the fort of Raj- 
mahal in Bahar on the 16th December, 1830. I also procured dead 
shells from the rocks of Patharghata. It appears to be very plentiful in 
all these situations. I never met with it to the westward, either in the 
plains or among the rocks or hills of the Vindhyan ranges which border 
those plains to the southward. I have seen a worn specimen in a collec- 
tion of shells made 22 or 23 years ago in Ceylon. 
The young shell being destitute of the thickened and continuous 
peristome, as well as of the rich orange colour which adorns that part, 
might, if met with destitute of an inhabitant, be easily mistaken for a 
Helix. The peristome when first reflected is also free from the orange 
colour, which it does not acquire until thickened and fully grown. 
In its exterior anatomy the animal differs from that of Cyc, elegans, 
