316 MR. H. ADAMS ON NEW FORMOSAN SHELLS. [May 22, 



4. Descriptions of Fifteen New Species of Land and Fresh- 

 water Shells from Formosa, collected by Robert Swinhoe, 

 Esq., Consul at Taiwan in that Island. By Henry 

 Adams, F.L.S. 



(Plate XXXIII.) 



1. Nanina (Acusta) assimilis, H. Ad. (PI. XXXIII. fig. 1.) 



N. testa aperte umbilicata, depressa-globosa, tenui, irregularitcr 

 striata et confertissime leviter decussata, subpellucida, nitida, 

 pallide fulva ; spira subconica, obtusa ; anfr. 5g, convexiusculis, 

 ultimo ventricoso ; apertura lunato-circulari ; pei'ist. simplici, 

 acuto, margine columellari arcualo, dilatato, ad umbilicum reflex- 

 iusculo. 



Diam. maj. 22, min. 18, alt. 15 mili. 



Hah. Takow, Formosa (Mus. Brit.). 



This species much resembles N. sieboldtiana, but is more widely 

 umbilicated, more depressed, and of a lighter colour. 



2. Helix (Plectotropis) fulvicans, H. Ad. (PI. XXXIII. 



fig. 2). 



H. testa umbilicata, trochiformi, tenuiuscula, oblique leviter striata, 

 et liris spiralibus tenuissimis decussata, breviter pilosa, pallide 

 fulva; spira conoidea, acutiuscula, sutura simplici; anfr. 6^, 

 subplanatis, ultimo subacute carinato, antice descendente, basi 

 convexiore ; apertura obliqua, subrhombea ; perist. tenui, margi- 

 nibus convergentibus, dexlro expanso, antrorsum subsinuoso, colu- 

 mellari peracuto, reflexo, umbilicum non claudente. 



Diam. maj. 11, min. 10, alt. 9. 



Hab. Tamsui, Formosa (Mus. Brit.). 



3. Helix (Cam^ena) bairdi, H. Ad. (PI. XXXIII. fig. 3.) 



H. testa umbilicata, turbinato-depressa, solida, oblique plicato-striata, 

 fulva, fascia peripherica nigro-castanea luteo-marginata ornata ; 

 spira breviter conoidea ; anfr. 6, convexiusculis, lente accrescen- 

 tibus, ultimo antice descendente, umbilico mediocri profundo ; 

 apertura diagonali, auriformi-lunari ; perist. fusco-carneo, ex- 

 panso et breviter reflexo, marginibus remotis, utrinque in medio 

 flexuoso et obsolete tuberculato, externe indentato ; margine colu- 

 mellari dilatato. 



Diam. maj. 41, min. 36, alt. 23 mill. 



Hab. Tamsui, Formosa (Mus. Brit.). 



4. Helix (Cam^na) succincta, H. Ad. (PL XXXIII. figs.4, 4a.) 



H. testa umbilicata, conoideo-depressa, solidula, oblique striata, 

 lineis spiralibus ?-vgosis irregulariter decussata, luteo-ftdva, 

 fascia peripherica pallido-marginata ornata ; spira conoidea ; 

 anfr. 6, convexiusculis, ultimo antice vie descendente, obtuse 

 carinato, basi compresso ; umbilico ungusto, interdum intus cas- 



