ORCULA. 31 



white, very little expanded, somewhat thickened within. 

 Parietal callus thickened close to the angle. Parietal lamella 

 strong. Columellar lamella rather strong, not emerging; 

 above it a lower, blunt supracolumellar. Internally the pari- 

 etal lamella is high and strong; on the left side its crest is 

 abruptly deflected outward, and a low oblong callous lump is 

 developed on the parietal wall external to the lamella ; beyond 

 the deflection, within the ventral side, the parietal lamella 

 becomes low. The columellar lamella is strong within the 

 back, the supracolumellar much weaker. Both are rather 

 robust. 



11. Orcula robusta (Naegele). 



Shell perforate, cylindric with obtusely conoid apex ; whorls 

 10-11, a little convex, obsoletely obliquely striolate, the upper 

 ones striate, glossy, corneous; the last whorl compressed 

 towards the aperture, forming a crest around the umbilicus, 

 with stronger stria?, ascending in front. Aperture angular at 

 base; peristome broadly reflected, the columellar margin 

 straight, outer margin arcuate, thickened in the upper part, 

 the margins joined by an extremely strong callus. Deep 

 within one columellar lamella; a parietal lamella joined to 

 the callus and diminishing inwardly. Length 21 [error for 

 12?], diam. 4 mm. (Naegele). 



Upper Euphrates: Balian-Keuy. 



Pupa (Orcula) robusta Naegele, Nachrbl. d. m. Ges., vol. 

 38, Jan. 1906, p. 28. 



This Orcula differs from its relatives especially by its sharp 

 basal keel, the angular aperture and by the very heavy cal- 

 lous connection of the columellar and outer margins. The 

 parietal lamella is united with the callus, but becomes weaker 

 as it enters. The columellar lamella stands deep within on 

 the upper part of the columella. In size this Orcula stands 

 near orientalis Parr. (Naegele). 



12. Orcula scyphus ('Friv.' Pfr.). PI. 3, fig. 1. 



Shell rimate, cylindric, striatulate, glossy, diaphanous, 

 brownish-corneous. Spire terminating in a very short, rather 

 acute cone. Whorls 11, rather flat, the last ascending in 



