110 



§ 2. Peritreme more or less reflected. 



57. C. BiLABiATUM. (pi. XXV. f. 81, 82.) noi, Pterocyclos 

 bilabiatus, Benson. 



T. discoidea, spira depressa, fere plana, colore pallido, 

 castaneo-undulata; anfractibus 5, rotundatis, gradatim 

 majoribus, laevibus ; sutura distincta, profundiuscxila ; aper- 

 tura fere circular!; peritremate duplici, interno simplici, 

 superne emarginato, externo extus undulato, sinuoso, superne 

 in tuberculum fornicatum desinente ; umbilico patulo, an- 

 fractibus distinctis; operculo circulari, spirali, intus coneavo, 

 extus convexo, lamelloso. 



Shell discoid, with a depressed, nearly flat spire, of a pale 

 colour, undulated with chestnut ; volutions five, rounded, in- 

 creasing gradually in size, quite smooth ; suture distinct, 

 rather deep ; aperture nearly circular, with a double peri- 

 treme ; inner peritreme simple, notched at the upper part, 

 outer one sinuous and undulated, running into a vaulted 

 tubercle at the upper part ; umbilicus large and spreading, 

 volutions distinct within ; operculum circular, spiral, concave 

 within, convex and lamellar externally. 



Brought from Salem, near Madras, by J. M. Heath, Esq. 



58. C. PLANORBULUM. (pi. XXV. f. 83 to 86.) Lam. Anim^ 

 sans. vert. vi. 2, p. 143. 



T. discoidea, spira depressa, plana, colore pallido, castaneo- 

 variegata; anfractibus 5, rotundatis, gradatim majoribus, 

 laevibus; sutura distincta, profundiuscula ; apertura fere cir- 

 culari, peritremate incrassato, superne et extus reflexo, 

 ultimum versus anfractum desinente, fomicato ; umbilico 

 patulo. 



Shell discoid, spire depressed, flat, colour pale, varied with 

 chestnut ; volutions five, rounded, increasing very gradually 

 in size, smooth, with faintly marked transverse lines of growth ; 

 suture distinct, rather deep ; aperture nearly circular, with a 

 thickened peritreme, the upper and outer part of which is 

 reflected, and forms a vaulted projection running upon the 

 last volution ; umbilicus wide, spreading, the volutions con- 

 spicuous within. 



Several varieties were brought by Mr. Cuming from the 

 Philippine Islands : it is also found in Bengal. 



59. C. spiRACULUM. (pi. xxxi. f. 270. 271. 272. var. f. 

 273.) nob. Genus Spiraculum nonnull. 



T. suborbiculari, planorbula, crassiuscula, albicante, casta- 

 neo radiatun irregulariter strigata, epidermide fuscescente 



