Mr. W. H. Benson on new forms £>/" Cyclostomacea. 225 



XVII. — Characters of seventeen new fur ins of the Cyclostoniacca 

 from the British Provinces of Burinah, collected by W. Theo- 

 bald, jun., Esq. By W. II. Benson, Esq. 



1. Alycaus pyramidalis, n. s. 



Testa perforata, pyramidato-conica, Iseviuseula, confertim oblique ar- 

 cuato-striatula, albido-carnea, apicem versus rubella ; spira pyra- 

 midata, sutura valde impressa, apice obtusiusculo ; anfractibus 5^ 

 valde couvexis, ultimo postice iiiflato, turn constricto, delude sub- 

 tumido, aperturam versus latiori, tubulo calloso, elongate, retro- 

 verso, suturali, ])oue constrictionem oricute, uiuuito ; apertura ob- 

 liqua, subcircvdari ; ])eristoinate duplici, interno coutiuuo, expau- 

 siusculo, exteruo exj)anso, reflexiusculo, anfractu peuultimo bre- 

 vissime angulatim adnato, superne autice sinuato, turn arcuato, ad 

 uuibilieum leviter emarginato. Operculo ? 



Long. 12, axis 10, lat. 10 mill. 



Hab. raro ad coUem Therabuin, vallis Tenasserim. 



Nearly related to the Cochin-Chinese Alycceus gibbus, Fer., 

 but easily to be distinguished by its more pyramidal growth, 

 and by the greater length of the spii'e in proportion to the 

 breadth of the last whorl, its more symmetrical proportions, 

 sculpture, &c. The origin of the sutural tube is about 4 milli- 

 meters from the anterior margin of the aperture. This shell 

 was met with at no other place in the district, and seemed 

 restricted to a spot of a few acres in circumfei*euce. The hill is 

 of limestone, steeply scarped and almost inaccessible. Three 

 species of Helix occui'red there which were similarly deficient 

 elsewhere. 



2. Alycaits umbonalis, n. s. 



Testa late umbilicata, depressa, subdiscoidea, confertim acute ar- 

 cuatim costulata, cincreo-albida, apicem versus obtusulum, rubel- 

 lum vel nigrum, rubcscente ; spira brevi, sutura profunda ; anfrac- 

 tibus 4 J convexis, ultimo ad latus, spiraliter rugoso-cancellatum, 

 inflato, turn constricto, delude tumidiusculo, tubulum retroversum, 

 elongatum suturalem pone constrictionem gerente ; apertura valde 

 obliqua, circular!, uudata, peristomate duplici, iutcriori coutiuuo, 

 expanse, nitidissimo, propc umbilicum sinuato, cxteriori exj)auso, 

 iucrassato, ad anfractum peuultimum breviter iuterrupto ; umbilico 

 perspective. Operculo corneo-fusco, nmltispirato, aufractuum mar- 

 ginibus scabre elevatis, extus profunde concavo, intus convexiusculo, 

 nitidissimo, sulco marginato, umboue centrali papillari munito. 



Diam. major 10, minor 8, axis ;j mill. 



Hab. ad Akaouktong, prope ripas iluvii Irawadi, nee raro. 



As the last-mentioned species exhibited a Cochin-Chinese 

 form, so does this shell represent, on a larger scale, the little 

 Western Himalayan species A. strangulatus, Hutton. The sca- 



Ann. 6f Mag. N. Hist. Ser. 2. Vol. xvii. 1 5 



