250 Mr. ^^ . II. Bcuson on new species of Burmese Helices. 



I'lovato, obtusi), s\iturii juofmula ; niifractibiis G-i aiigustis, Icnte 

 nccresci'iitil)us, uUiiiio suponie sul)aiigulato, subtiis couvexiusculo ; 

 apcrtura siib-angustc liiiiat.i, obliijua ; jtciistomate acuto, leviter 

 sinuato, niarf^ine coluniellaii brovissiino, basaliquc cxpausiusculo, 

 dextro crcmilato. 



Diani. major 14, minor 12, axis ;") mill. 



I/dfj. ad IMiie Tlian vallis Tenasscrim. Teste W. Theobald. 



The sculpture of this discoid species is very elaborate, aud 

 strouirly pronouuccd iu proportiou to the size of the shell, pre- 

 senting; a very beautiful a})i)carance under the lens. The ends 

 of the spiral lirse give a sealloj)ed edge to the outer lip. 



3. Helix cnpessens, n. s., nobis. 



Testa imperforata, depresso-couoidca, supcrne radiatim costulato- 

 striata, subtus Ifeviori, rufo-cornea ; sjiira subconoidea, apice ob- 

 tusiusculo, sutura impressa ; anfractibus Q\ convexiusculis, lente 

 accrescentibus, ultimo acute carinato, antice leviter depresso, subtus 

 couvexiusculo, ad ])eriomphalum excavato ; apertura transversa, 

 angusta, dentibus 3 basalibus eequalibus coarctata, margiue recto, 

 obtuso, vix sinuato. 



Diam. major 9, minor 8, axis 4 mill. 



Hah. ad Maulmain. Teste W. Theobald. 



Nearly related to //. infrendens, Gould, which was found by 

 Mr. Theobald at the Rangoon Caves on the Salvveen River, but 

 easily distinguished by its more depressed form, keeled periphery, 

 and the more regular dentition of the basal margin. The ])rofile 

 of the spire is less convex, and the last whorl is depressed in 

 front below the level of the keel of the ])enultimate whorl, 

 whereas in //. infrendens it ascends at the same part. H. capes- 

 sens fonns, with H. pyluica, a notable addition to the restricted 

 section Tridopsis. 



4. Helix convallata, n. s., nobis. 



Testa vix perforata, convexo-depressa, tenui, nitidissima, radiato- 

 striata, translucentc, olivaceo-coraea ; spira convexiuscula, apice 

 prominulo obtuso, sutura profunde canaliculata ; anfractibus 6 

 convexis, lente accrescentibus, prope suturam acute angulatis, ul- 

 timo rotundato, non descendente, subtus convexiusculo ; apertura 

 vix obliqua, luuata ; peristomate acuto, superne ])rope suturam 

 angulato, antrorsum leviter arcuato, margiue columellari oblique 

 descendente, cxpausiusculo. 



Diam. major 14, minor II i, axis \-ix 7 mill. Apert. lata 7, alt. 5 mill. 



Ilab. ad collem Therabuin vaUis Tenasserim. Detexit W. Theobald. 



Singular among the allies of Helix vitrinoides on account of 

 the excavated canaliculate suture with a carinate margin. 



