196 Mr. W. H. Benson on two species 0/ Pterocyclos. 



interesting genus, of which eleven distinct Asiatic species may 

 now be enumerated, viz. : — 



1. Pterocyclos rupestris, Benson, 1832, Bahar. 



2. hispidus, Pearson, 1833, Khasya Hills. 



3. parvus, Pearson, 1833, Khasya Hills. 



4. anguliferus, Soul. 1H41, Cochin China. 



5. hilabiatus, Sow. 1843, South India. 



6. Albersi, Pfeiffer, 1847. 



7. biciliatus, Mousson, 1849, Burma. 



8. spiracellum, Ad. & Reeve, 1850, Borneo. 



9. Cuminyi, Pfr. 1851, Ceylon. 



10. Blandi, nobis. Straits of Malacca. 



1 1 . Troscheli, nobis, Ceylon. 



Full descriptions of the species, and the specimens themselves, 

 having been so long withheld from the public eye, I have over- 

 come my objection to publish characters, founded on the only 

 materials available, in the hope that more particular attention 

 may be directed to these shells by travellers who may have oppor- 

 tunities for exploring the localities whence they were obtained. 



Pterocyclos Blandi, nobis. 



Testa latissime umbilicata, orbiculato-depressa, albida, strigis undatis 

 radiatis fusco-aurantiis, fasciaque unica saturatiore ad periphaeriam 

 omata ; anfractibus 4^ rapide accrescentibus, ultimo antice subito 

 valde alatim dilatato ; apertura obliqua, peristomate subduplici, 

 interne incrassato, superne libero sinuate, externo superne valde 

 expanse, ala soluta antice angulata, descendente, supra anfractum 

 penultimum projecta, pestice sinum exhibente munito ; umbilico 

 latissime. 



Diam. 1 inch. Bland. 



Diam. major 29, minor 23 mill, ex icone. 



Hab. ad Pule Susson insulam prope Pule Penang jacentem. Teste 

 Bland. 



Pterocyclos Troscheli, nobis. 



Testa latissime umbilicata, erbiculate-depressa ; anfractibus 4 lente 

 accrescentibus, ultimo antice subdilatato ; apertura circulari peri- 

 stomate incrassato, reflexo, superne antice obsolete sinuate, ala cu- 

 cullata, antice angulata, deflexa, anfractui penultime adhaerente ; 

 umbilice latissimo. 



Operculo cenvexo, cornee. 



Diam, ■^-^y inch. Bland. 



Diam. major 20, minor 18 mill, ex icene. 



Hah. ad Trincomalee Insulse Ceylon. Teste Bland. 



In character it approaches the group Myxostoma of Troschel, 

 to whom I have the pleasure of dedicating this species of a genus. 



