416 Mr. W. H. Benson on the Geographical Distribution 



Kemaon, Sirmore, and as far as the banks of the Sutlej, The 

 only other species known occurs in Cochin-China, 



Megalomastoma, Guilding. 



This form is confined to the Eastern Himalaya, and presents 

 only two species, M. funiculatum, nobis, from Darjiling, and M. 

 pauperculum, Sow., brought by Gi'iffith from Bootan, to the 

 north of the Assam valley. The nearest known point at which 

 it again appears is Tavoy, where M. sectilabre, Gould, is met 

 with. In Ceylon it is represented by eight different species of 

 the allied form, Cataulus. 



Pterocyclos, Benson. 



Appears in the south-east angle of the Berhampooter river in 

 Pt. hispidus and parvus, Pearson ; again, across the plain of 

 Bengal, in the Rajmahal range, we find the typical species, Pt. 

 rupestris, nobis. Near the eastern coast of the peninsula, iu 

 the Northern Circars, the same species is repeated; and near 

 Salem, and at the eastern foot of the Nilgherries, Pt. bilabiatus, 

 Sowerby, and nanus, nobis, form a link with the Cingalese 

 representatives of the genus. 



Cyclotus, Guilding. 



Occupies a subcentral zone. It was detected at Neemuch, 

 to the north of the Nerbudda, in Southern Rajpootana, by 

 Captain Hutton, in C. semistriatus, Sow., and the Dekkan habitat 

 of the species cited by Sowerby has been lately verified by my 

 son, who has taken it at Kirkee, a few miles from Poonah. A 

 second species, C. semidiscoideus, Sow., (aratus, nobis), occurs 

 in the Northern Circars, near the east coast of the peninsula*. 

 It may be observed that the Cochin-Chinese species described 

 and figured by Souleyet, in the c Voyage of the Bonite/ as 

 Cyclostoma Tourannense, and placed by Pfeiffer in the list of 

 species only known to him by figures, is clearly to be referred 

 to Cyclotus from the description of the operculum ; although 

 that accessory piece has apparently been exchanged, by the 

 engraver of the plate, with the operculum of the Penang Lepto- 

 poma [Cyclostoma) Garreli, Soul. 



Leptopoma, Pfeiffer. 



I have no certain information of the occurrence of this genus 

 in the tract under consideration. I have described two species 



* The discovery of an operculum in a specimen of Cyclostoma filocinctum, 

 nobis, from the Nilgherries, enables me to range it as a third species of 

 Cyclotus, belonging to the same division as C. substriatus, Sow. The 

 characters of the shell confirm the propriety of this location. 



