338 Rev. R. T. Lowe on two new Madeiran Land-Shells. 



XXXIII. — Description of two new Madeiran Land-Shells lately 

 discovered by the Barao do Castello de Paiva and S^ J. M. Moniz. 

 By R. T. Lowe, M.A. 



The two following valuable additions to the Helicological Fauna 

 of Madeira are at once proofs of the inexhaustibility of that 

 singularly fertile region and of the acumen and activity of its 

 present explorers. The discovery of a new semifossil Helix in 

 the S. Deserta, belonging to a group so imperfectly represented 

 in Madeira as Euromphalus, Beck, is scarcely less interesting 

 than that of a fourth species of Clausilia in addition to the very 

 small number of that genus, proportionately to the Helices and 

 Pujxs, previously observed in Madeii'a. The fossil Desertan 

 Helix is indeed so nearly allied to H. Gueriniana that it may 

 reasonably be expected to reward future research, in the remoter 

 sylvan districts of Madeira proper, in a living state. It is, at ail 

 events, a proof how closely the topographic and climatic condi- 

 tions of even the Desertas must have formerly resembled those 

 of the principal island of the group, from which they are now in 

 all respects so widely separated. 



1. Helix calathoides, Paiva, MSS. 



Testa latissime et perspective concavo-umbilicata, subtus excavata, ro- 

 tundata, utrinque convexiuscula, arctispira, obsolete v. obtuse ca- 

 rinato-angulata, subsolidiuscula ; supra grosse crebricostata, costis 

 prominulis ad anguluiB abrupte desinentibus ; subtus obsolete vix 

 striatula, laevigata ; spira convexiuscula, subconoideo-depressa, 

 apice obtusa, laevigata ; sutura distinctissima, valde impressa ; 

 anfr. 7-8, convexiusculis, lente crescentibus, ult. antice recto, baud 

 deflexo, supra carinam obsoletam crebricostato, convexiusculo, 

 subplanato, infra ecostato, Isevigato, rotundato-convexo ; umbil. 

 latissimo, infundibuliformi, pervio, patulo, profundo ; apertura 

 oblique ovali, altiore quam lata ; peristomate simplici, recto, tenui, 

 acute. 



Diam. maj. 7-8, min. 6|^-7i, alt. 3-4 mill. 



Hab. semifossilis in insula Deserta australi "Bugio" dicta. 



Very closely allied to the Madeiran recent H. Gueriniana, Lowe 

 {H. semiplicata, Pf.), but assuredly a genuine species, and not a 

 merely large fossil form of that shell. It is distinguished by its 

 larger size, less discoidal shape, greater convexity beneath, more 

 elevated spire, obsolete keel, deeply impressed suture, and much 

 coarser, more abrupt, and prominent ribs above, resembling, in 

 the latter respect and in the abrupt ending of the ribs at the 

 obsolete keel or angle of the last volution, H. Calathus^ or H bi- 

 frons, Lowe. Not much reliance can be placed on its greater 

 thickness of substance as Compared with H. Gueriniana, seeing 

 * According to Pfeiffer = H. stephanophora, Desh. in Fer. 



