26 CATALOGUE OF PHANEROPNEUMONA. 
columellar margin thickened, shortly affixed, separated by a 
deep notch from the upper one, which is dilated like a wing. 
Opere.? Height 15, greatest breadth 40, least br. 32 mill. 
Cyclostoma incomptum, Sow. Thes. Suppl. n. 183, p. 160%, t. 31, A. 
f. 298, 299. 
Pterocyclos incomptus, Pfr. in Z. f. M. 1851, p.9; Jc. t. 31, f. 1, 
2; Consp.n. 45; Pneum. Mon. p. 42. 
Hab. India? (Sowerby); Brazils (Cuming). 
§ 2. Peristome double. Operculum externally nearly flat, with the 
outer whorls raised in lamella. Myxostoma, T’rosch. 
2. PrmpROCYCLOS BREVIS. B. M. 
Shell conoid-semiglobose, solid, slightly striate, a little shining, 
chestnut-coloured, with fulvous spots and stripes ; spire short, 
rather blunt; suture broadly impressed, bordered; whorls 5, 
convex, the last one angularly compressed round the broad 
and funnel-shaped umbilicus; aperture rather circular, white 
inside; peristome thickened, reflected, produced above in a 
triangular beak, which is closely pressed to the penult whorl, 
deeply channelled internally, and forms externally a broad, 
prominent, knot. Operculum blackish. Height 22, greatest 
breadth 36, least br. 30 mill. 
Lituus brevis, Martyn, Fig. of non-descr. Shells, t. 28, c. ed. Chenu, 
(Bibl. Conch. ii.), p. 21, t. 8, f. 2. 
Turbo Petiverianus, Gray, in Wood, Ind. Suppl. t. 6, f. 2. 
Cyclostoma Petiverianum, G'ray, 2 Wood, Suppl. p. 36; Sow. Spec. 
Conch. f.97,98; Thes. n. 74, p. 116, t. 25, f. 100, 101; Reeve, 
Conch Syst. ii. t. 184, £.15; Petit, in Journ. Conch. i. p. 43. 
Cyclostoma breve, Pfr. Je. p. 116, n. 180, t. 24, f. 1, 2. 
Myxostoma Petiverianum, 7’rosch. in Z. f. M. 1847, p. 44. 
Myxostoma breve, Pfr. ibid. p. 111; Gray, Cat. Cyc. p. 15, n. 1. 
Pterocyclos brevis, Pfr. in Z. f. M. 1851, p. 9; Consp. n. 46; 
Preum. Mon. p. 42. 
Hab. India, Pulo Condore. 
3. PrerRocycLos PLANORBULUS. B. M. 
Shell depressed, discoidal, rather solid, striate, and irregularly 
foveate, fulvous, with crowded angular reddish-brown radiating 
lines; spire flat, with the apex scarcely prominent; suture 
deep, channelled; whorls 5, moderately convex, the last one 
nearly cylindrical, with a blackish band at the periphery, white 
round the very broad umbilicus; aperture oblique, rather circu- 
lar, blueish-white inside ; peristome double ; inner edge shortly 
expanded, indented above with a triangular notch; external 
edge scarcely broader, expanded, dilated into a disjoined wing 
above the notch. Operc. like that of C. brevis. Height 12, 
greatest breadth 39, least br. 31 mill. 
