94 Mr. W. n. Benson on new Terrestrial Shells from Ceylon. 



direct elonp;ation of the intcniiil coat, like the spores of the 

 Zygnemaccie fonmd throuj^h conjugation, while the spores of 

 Bulbucluetc, and perhaps the spores of the Desniidicjc, hkewisc 

 ori^jinating through conjugation, behave in the same way as those 

 of Sji/ui'ioplea. This inchices us to regard the hitter fact as a 

 pccuHar form of the ' ahernation of generations/ if we dcno- 

 niinate the ' swarming-eclls ' produced from the spores of 7i»//;«- 

 c/ui'fe and Splueroplea an asexual generation, which by mcta- 

 nu)rj)hosis is converted at once into the C/us(erium-\ikc g(;rm, 

 then by asexual division produces the sexual cells, till the cycle 

 is concluded by the formation of the impregnated spores. 



X. — A^ew Terrestrial Shells from Ceylon, ivifh a General List of 

 the Species inhabiting that Island. By W. H. Benson, Esq. 



Cyclophorus Parma, nobis, n. s. 



Testa latissime umbilicata, planato-dcprcssa, discoidoa, tcnuiuscula, 

 confortiin et arcuatim scricato-striata, saturate castaiica, tlaiiumilis 

 noninilUs ])allidissiiiram versus ornata, subtus iutcnluni pallidiori ; 

 spira planata, ai)ice nullo inodo promincute, sutura jjrofunda ; 

 anfractibus .") convcxis, ultimo antice descendcute ; ajjcrtura valdc 

 obliipia, ainpla, ovato-rotuudata, superue angulata, intus livide 

 caerulca ; peristomate duplici, intcriori continuo, albido, ad dextram 

 expausiusculo, extcriori Ijreviter interrupto, cxpjinsiusculo, fusco- 

 corueo ; margine colunicllari subtus reccdcntc, dextro prorsuin ar- 

 cuate ; unibilico latissimo, minime profundo. (Jperculo teuui, cor- 

 neo, .5|-spirato, suturis intus extusque pulchre carinatis. 



Diam. major 2G, minor 23, alt. C mill. 



Hab. in regione montana Insulae Ceylon. Mus. E. L. Layard. 



There are two specimens in the cabinet of Mr. Edgar Layard. 

 The shell is easily distinguished from the other planorbular 

 Cycliiphori of Ceylon by its dark colour and depressed form, 

 which recall those of Pterocyclos Idspidus, Pearson, by its very 

 wide and shallow umbilicus, and by the size and peculiar position 

 of the aperture. The whorls of the operculum, which is of a 

 clear horn-colour, arc less closely wound than in C. Cratera. 



Cyclophorus Cratera, nobis, n.s. 



Testa late umbilicata, planulato-depressa, subdiscoidea, tcnuiuscula, 

 radiatim ct confertirn ruguloso-striata, vix nitidula, fulvo-coruea, 

 raro castaneo-strigata ; si)ira plauulata, apice vix [)rominente, su- 

 tura j>rorundiuscula ; anfractibus .0 convexiusculis, ultimo longe 

 leiitcfjue dcsccndeiite ; apertura oblicpia mediocri, subrotundata, 

 superue angulata, intus albida ; peristomate duplici, iuteriori con- 

 tinuo, acuto, breviter porrecto, cxteriori expansiusculo, breviter 

 adnato, albido ; umbilico aperto, profundiusculo. Operculo tenui. 



