130 Mr. W. H. Benson on Tanystoma tubiferum. 



Tanystoma, nobis. 



Testa coiiToluta, conoidea; umbilicus apertus ; anfractus viltimus 

 solutus, protractus, sursum tortus, aperturam deutatam alte tolleus; 

 peristoma horizoutale, expansum. 



T. tuhiferum, nobis. 



Testa depresso- conoidea, radiato-striata, cornea, sutura excavata, 

 spira breviter conoidea, apice obtiisiusculo ; antVactibus 3, convexis, 

 ultimo tubam protractam, sursum tortam, altiorem quam apice, 

 efformante, ad periphseriam valide et obtuse carinato, superne 

 baltea tumida, a peripbseria sulco profuudo separata, munito, 

 subtus convexo, margine umbilici a])erti perspectivi angulato, 

 augulo usque ad aperturam extendente ; apertura borizontali, 

 sursum spectante, 6-7-dentata, dentibus lamelliformibus duabus 

 parietalibus, supera validiori duplicata, iuferiori minore profunda, 

 1 columellari mediocri, 4 palatalibus, quarum superiori duplicata 

 tertiaque majoribus ; peristomate libero, valde expanso, reflexi- 

 usculo. 



Diam. major 4, min. 3, axis 2 mill. 



Habitat ad Thyet-jSIio prope ripas fluminis Irawadi Burmanici, saxis 

 calcareis adhserens. 



This interesting shell was found by Mr. Theobald to be very 

 local, but not uncommon at the spot indicated — about six miles 

 south of the frontier station. It was not met with lower down 

 the river at Pi'ome, nor elsewhere. 



Cyclophorus fulguratus, Pfr., was found from Thyet-Mio to 

 Rangoon; and a gigantic Megalomastoma, of the type of M. 

 Chrysallis, PfeifFer, resembling in size and figure Piipina grandis 

 of Forbes, near Moulmein, verifying the opinion communicated 

 to Dr. PfeifFer, that the true habitat of those two species was 

 probably Ava, and not Arva, a river in Columbia, as conjectured 

 by that author from the illiterate orthography of the name fur- 

 nished to him. 



Five new species of Gray's genus Alycceus occurred, two of 

 which are related to the Himalayan A. strangulatus, H., and 

 A. gihbus of Cochin China. There are also two ncAv forms of 

 Pterocyclos, two of Pupina, besides a third from Sylhet, a new 

 Leptopoma, an Otopoma (?), and two or three new Cyclophori. 

 Two new minute Hydrocence, closely allied to my Khassya Cycl. 

 sarritum, with the operculum, enable me to fix the place of that 

 species, as well as of C. tersum, mihi, and probably of C. Milium, 

 both of which PfeifFer, in a letter dated some months ago, con- 

 jectured to belong to Hydrocena. Cyclotus and Dipihmmatina, 

 which are Indian forms, are not represented in the collection. 



In new Helices the collection is very rich : one form in par- 



