1882. } MOLLUSCAN FAUNA OF MADAGASCAR. 377 
The peristome is very similar; and the sculpture is somewhat of the 
same character. Still there are differences of form, of colour, in the 
sutures, and in the size of the aperture, which readily distinguish 
these forms, which no doubt inhabit different districts of the island. 
Var. a. 
Shell with a less elevated spire, shorter and broader whorls, more 
widely umbilicated, with a larger and more oblique mouth, and the 
outer lip not stained with rose. 
Greatest diam. 30 millim., height 24. 
Hab. Betsileo (Cowan). 
Var. 6 (Plate XXI. fig. 3). 
Shell a trifle more ventricose than var. a, with the umbilicus 
similar to that of the type, but the aperture larger and the peristome 
white, with the body-whorl smoother, with fewer and subobsolete 
spiral liree, except within and around the umbilicus. 
Greatest diam. 30 millim., height 263. 
Hab. Betsileo (Cowan). 
CycCLOSTOMA CONGENER, sp. nov. (Plate XXI. fig. 1.) 
Shell openly umbilicated, subdepressedly turbinate, rather smooth, 
_ obsoletely spirally sulcate, striated with lines of growth which are 
puckered and distinct at the sutures; bright yellow, longitudinally 
streaked with a darker tint, dark cinereous behind the white expanded 
lip, encircled at the periphery by a vivid purple-brown band and 
with two or three hair-like lines of a paler colour, both above 
and below the middle. Spire elevated, conical, ending in a bluish 
obtuse tip. Whorls 53, very convex; the last large, strongly lirate 
around and within the umbilicus, where it is stained with purple- 
brown. Aperture large, oblique, ovate-subcireular, light brown 
within except near the lip, where it becomes of a very dark chestnut- 
brown or nearly black, this colour extending along the inside of the 
columellar edge. External band and lines visible within. Peristome 
roundly expanded and reflexed, white, broad on the dextral margin, 
narrower on the columellar side. 
Greatest diam. 34 millim., height 30. 
Hab. Tanala province (Cowan). 
This form approaches most closely to C. consanguineum of Sowerby 
(= C. obsoletum of Reeve, not of Lamarck), but may be distin- 
guished by its greater size, its yellow colour, dark apex, and rather 
more elevated spire. Both species have the same disposition of the 
spiral bands and lines—namely a single central broad zone, two 
narrower ones between it and the suture, which are visible on the 
spire, and two others beneath it and around the lower surface of the 
whorl. In some specimens of C. consanguineum some of the sulci 
around the umbilicus are also of a dark colour. On holding up a 
specimen of C. congener to the light, three lines above and three 
below the broad band are generally observable. C. obsoletum of 
Lamarck, according to Delessert’s figure (Recueil, pl. 29. f. 11a) 
