112 ANOSTOMA. 



with a corneous epidermis, composed of 5 convex whorls. Spire 

 obtuse; suture hardly impressed, not marginate, bordered below by 

 a blackish band. Last ivhorl globose, not carinated, divided by a 

 submedian blackish band above, the upper part having only a few 

 spots near the periphery, the base with numerous brown spots 

 arranged concentrically. Aperture semilunar, a little oblique, the 

 columellar [parietal] margin arcuate, convex, three-toothed, the 

 median tooth most strongly developed ; peristome white, reflexed, 

 provided with six equidistant and equal white teeth, violaceous at 

 their bases. Alt. 18, greater diam. 33, lesser 24 mill. (Fischer). 



Brazil (Deshayes coll.). 



Anostoma deshayesianum FISCHER, Journ. de Conchyl. v (2d ser., 



vol. i), p. 350, pi. 12, f. 1, 2 (Jan., 1857) PFR., Monogr. iv, p. 



326 ? ? REEVE, Conch. Icon., f. 5 a, b. 



Differs from A. octodentatum by the more globose form, absence of 

 a carina and arrangement of the teeth, there being two teeth (col- 

 umellar lamella and basal fold) instead of but one, upon tne lower 

 margin of the lip. Judging from the figure, the median tooth of the 

 parietal margin is less oblique than in A. octodentatum. Reeve's 

 figure is probably a small form of A. octodentatum, not the real 

 deshayesianum. 



A. DEPRESSUM Lamarck. PL 6, figs. 48-54. 



Shell biconvex, the alt. about half the diameter, angular at the 

 periphery, whitish, more or less brown-tinted, the base dappled with 

 oblong spots or streaks arranged concentrically, having a dark band 

 along. the basal suture, the upper surface sparsely spotted near the peri- 

 phery, and having a brown band revolving below the suture, usually 

 with a fainter one above it. Surface finely striate above and below, 

 fresh specimens showing dense fine spiral lines, especially on the last 

 whorl. Whorls 4J|, nearly fiat, the last angular or carinated at the 

 periphery, its last half straightened and turned upward, showing two 

 or three grooves or pits behind the lip. Aperture subhorizontal, 

 semicircular, obstructed by 5 or G teeth ; peristome expanded and 

 reflexed, pinkish-brown or fash tinted. Parietal margin bearing two 

 or three teeth ; a minute tubercular angle-lamella often obsolete, an 

 erect, compressed parietal lamella, and a small infraparietal lamella 

 at about the middle of the parietal margin. Outer margin with 

 three (or four) folds ; columellar fold usually wanting ; upper and 



