42 ORCULA. 



14&. Orcula raymondi bifilaris (Mouss). PL 4, fig. 9. 



Shell small, closely riinate, ovate-cylindric ; smoothish, orna- 

 mented with widely-spaced and fugacious membranous lami- 

 nas, rufous-corneous. Spire closely coiled, more rapidly de- 

 creasing above, the summit obtuse ; suture somewhat im- 

 pressed. Whorls 8, the first convex, following ones rather 

 flattened; the last whorl slowly ascending a little, rounded, 

 rather swollen beneath. Aperture subvertical (12° with the 

 axis), semicircular. Peristome white, reflected, lipped within, 

 the margins remote, parietal wall having a regular parietal 

 lamella ; right margin somewhat sinuated below the insertion, 

 then a little thickened and bent forward; columellar margin 

 broadly spreading, with two revolving threads, the upper 

 minute, immersed, the lower larger. Length 4.1, diain. 2.3 

 mm. (Mouss.). 



Transcaucasia. 



0. bifilaris was at one time thought to be merely a form of 

 doliolum (Reinhardt, Jahrb. d. m. Ges., iv, 1877, p. 76, and 

 Boettger, vi, 1879, p. 31; also p. 404), but Boettger subse- 

 quently relinquished this opinion, and considered it a variety 

 of 0. raymondi. The lamella? of bifilaris are somewhat less 

 broadly developed within the last whorl than in trifilaris; 

 there is more space between the parietal and the columellar. 

 The specimen figured from the Oschten-Fischt range, meas- 

 ures, length 4.1, diam. 2 mm. ; fully 8 whorls. 



0. raymondi bifilaris form longior (Ret.). Differs from the 

 typical form of bifilaris, found by me in various places in the 

 Caucasus, by its significant size, larger aperture, more pro- 

 duced apex as well as the more twisted columella. It stands 

 in the same relation to bifilaris as trifilaris Mouss. to ray- 

 mondi Bgt. Length 4.9 to 5.7, diam. 2 to 2.25 mm. Samsun 

 (Retowski, 1889). 



A conspicuously truncate form from the drift of the Pse- 

 kup has been named P. bifilaris truncata Rosen (pi. 4, fig. 8). 



0. raymondi bifilaris f. intermedia (Ret.). Whorls 9; 

 peristome connected. Columella with three folds, a short 

 third one further out placed between the usual two. Length 

 6, diam. 2% mm. By the presence of the short third fold 



