1882.] MOLLUSCAN FAUNA OF MADAGASCAR. 387 



Strongly lirated for this genus. It is a smaller form than P. mada- 

 gascariensis, has a shorter and more obtuse spire, a narrower per- 

 foration and spiral striation. P. lirata is more strongly lirate than 

 it, has the spire even still shorter, the body-whorl is prominently 

 shouldered above, and the aperture is longer in proportion. 



Planorbis madagascariensis, sp. nov. (Plate XXII. figs. 

 20-22.) 



Shell moderately thick, deeply excavated both above and below, 

 corneous brown, rather strongly striated by the lines of growth, 

 and sojnetimes exhibiting traces of spiral striation. Whorls 4-4^, 

 rapidly increasing ; the last large, rather high, convex, rather deeply 

 incurved at the suture both on the upper and underside, finely 

 malleated, chiefly round the middle. Aperture largish, broadly 

 lunate, raised above or on a level with the penultimate whorl. 

 Peristome thin, receding at the base, its extremities connected by a 

 very thin deposit of callus on the whorl. 



Greatest diam. 12g millim., smallest 10, height 4|. 



Hab. Lake Itasy \Johnson). 



This species is very like P. pfeifferi, Krauss (Sudafr. Moll. pi. v. 

 f, 7), but may be distinguished by the malleation of the last whorl, 

 its greater height, and browner colour . 



Neritina gagates, Lamarck. 



Neritina gagates, Lamarck {vide Martens, Conch. Cab. p. 94). 



Hab. Tamatave {Cowan). 



Two specimens from the above locality I believe to belong to this 

 species, differing only in the deep red colour of the columellar 

 callosity, and the olive-green tint of the outer lip. The form is the 

 same ; and the denticles on the columella, the painting, the micro- 

 scopic spiral sculpture, and the operculum are all similar. 



Neritina fulgetrum. Reeve. (Plate XXII. figs. 23, 24.) 



Neritina fulgetrum, Ueeve, Conch. Icon. pi. 23. f. 103 a, sp. 103. 



Hab. 1 {Reeve) ; south of Tamatave {Johnson). 



This species has hitherto been represented by a single specimen 

 without any locality in the Cumingian collection, now in the British 

 Museum. As the description in the •' Conchologia Iconica ' is very 

 short and incomplete, I will here add a few further details. The 

 black zigzag lineolation at times is very close, thus giving the shell 

 a greyish appearance when viewed at a distance ; and a character not 

 referred to by Reeve, but indicated in his figure, is the brown margin 

 to the body-whorl at the suture, beneath which the volution is faintly 

 constricted. The columellar callosity is much thickened and of a red 

 colour, and extends some distance over the whorl. The edge of the 

 columella is pale, straight, with a shallow sinus a little below the 

 middle, furnished with about a dozen denticle?. The aperture is 

 rather small, bright yellow far within, then whitish, and again yellow 

 or greenish-yellow at the lip. The operculum is slaty black ex- 



