ORCULA. 2o 



On the preceding page (31) Boettger had suggested that the 

 form with a single fold might be called unifilaris. This name 

 was proposed in a casual and tentative manner, in a para- 

 graph mainly discussing bifilaris Mouss., so that Kobelt 

 (Iconogr. n. F., viii, 1899, p. 76) erroneously supposed that 

 unifilaris was a form of bifilaris. Zalka may be considered 

 type locality for unifilaris, if it turns out to have any racial 

 value. 



Retowski notes that the specimens from Samsun belong to 

 the small form not uncommon in the Caucasus, all having 

 two distinct columellar lamella?. 



6a. Orcula doliolum tereticollis West. 



Shell short, obese, rounded-conic at apex, more strongly 

 and distantly lamellose-costulate ; whorls 8, very slowly in- 

 creasing, the last very narrow behind, not higher than the 

 penult, terete (not slowly, obliquely tapering downwards) ; 

 aperture semirotund, the parietal lamella long, one columel- 

 lar, thin, situated above, somewhat produced outward, peri- 

 stome widely spreading, outwardly thin. No punctiform 

 angular tooth (always present in the typical form). Length 

 4, width 1% mm. Northern Persia, Siaret, one specimen, 

 Keyserling and Bienert [Pupa (Orcula) doliolum var. tereti- 

 collis Westerlund, Annuaire Mus. Zool. Acad. Imp. Sci. St. 

 Petersb., i, 1896, p. 195]. 



6b. Orcula doliolum turcica 'Bgt.' Let. PI. 2, figs. 5, 6. 



Long, cylindric, pale brown somewhat translucent, sharply, 

 finely striate above, the cylindric part weakly so ; in the most 

 perfectly preserved individuals having delicate, well-spaced 

 cuticular riblets, more or less distinctly legible. Suture im- 

 pressed, shortly but rather steeply ascending to the aperture 

 in some examples, very slightly and slowly in others. Peri- 

 stome white, narrowly reflected, a little thickened within; 

 parietal callus thin, tuberculate next to the lip-insertion. 

 Parietal lamella of medium size, tapering in front, emerging 

 nearly to the edge of the parietal callus. It continues nearly 

 of equal height to the inner end. Columellar lamellae are not 

 visible in the mouth in some individuals (typical, according 



