288 MR. E. A. SMITH ON SHELLS FROM [Feb. 1 5i 



25. LiTHOGLYPHUs RUFOFiLosus. (Plate XXXIII. figs. 20, 20a.) 

 Lithoglyphus rufofilosxts, Smith, Ann. & Mag. N. H. 1 880, vi. p. 426. 

 Shell globose, thick, rimate, white, encircled with very fine, 



thread-like red lines, covered with a very thin epidermis. Whorls 

 5|, rapidly increasing, convex, separated by a simple deepish suture, 

 striated by the lines of growth ; last whorl large, globose. Aper- 

 ture also large, inversely rather pyriform, whitish, occupying about 

 I of the entire length of the shell. Peristome continuous. Outer 

 lip thin ; base and columella thickened, the latter particularly so, 

 and reflexed. Length ISmillims., greatest diameter 11^ ; aperture 

 \Q^ long, 6 broad. 



()perculum dark brown, ovate, straighter on the inner or colu- 

 mellar side, paucispiral in the centre, which portion is surrounded 

 by concentric layers. 



Hah. Lake Tanganyika (Thomson). 



The operculum of this species resembles that of Tiphoiia in 

 miniature. The centre of it is paucispiral or littorinoid ; and this 

 part is inclosed by a border which apparently consists of concentric 

 layers. The number and distance apart of the thin red lines are 

 subject to variation, one specimen having as many as twelve upon 

 the body-whorl, and another as few as four, 



Syrnolopsis. 



Syrnolopsis, Smith, Ann. & Mag. Nat. Hist. ser. 5, vol. vi. p. 426 

 (1880). 



Shell subulate, smooth, imperforate. Aperture broadly sinuated 

 at the base, with the outer lip slightly thickened, widely sinuated 

 in the middle, and produced towards the lower part, furnished far 

 within with one or two prominent lirse. Columella thickened, with 

 a distinct plait at the upper part, and joined to the upper extremity 

 of the labrum by a thin callosity. Operculum unknown. 



This curious form has all the appearance of a marine genus, in 

 fact closely resembling Obeliscus or Syrnola. The basal sinuation 

 of the aperture is similar to that in some species of Rissoina ; but 

 the plication on the columella is wanting in that group. This is 

 uot very prominent in the adult shell ; uor are the two lirae within 

 the aperture visible, except through the semitransparent shell, unless 

 the lip is broken away. On removing a portion of it these become 

 apparent, the upper one being the thicker and extending parallel 

 with the suture tor about the distance of half a whorl, the lower one 

 being shorter and more slender. The fold on the columella becomes 

 remarkably prominent as it ascends the spire ; and this may be ob- 

 served by grinding off one side of the shell. As nothing is known 

 of the animal, the systematic position of the genus is doubtful ; how- 

 ever, it may temporarily be classed with the Rissoidse. 



26. Syrnolopsis lacustris. (Plate XXXIII. figs. 21-21 b.) 

 Syrnolopsis lacustris, Smith, loc. cit. 



Shell smooth, glossy, elongate, subulate, imperforate, yellowish 



