4 ORCULA. 



the back are strong and subequal. Below them is an infra- 

 coluniellar which does not penetrate. The parietal lamella is 

 a whorl long, and the angular tubercle is well developed. 

 The shell is apparently of quite as modern type as some of 

 the recent Alpic species. The specimen figured is from the 

 Landschneckenkalk of Hochheim-Florsheim. 



Orcula amblya (Bourg.). Pupa amblya Bourguignat, 

 Paleont. Moll. Algerie, 1862, p. 75, pi. 4, f . 11-13. Pliocene ? 

 Oued Tademit, 15 leagues southwest of Djelfa, Algeria. A 

 species probably near 0. doliolum, 9-12 mm. long, 2-2.7 wide, 

 of 10-12 whorls. The parietal lamella is rather small; no 

 columellar folds mentioned or figured, therefore evidently 

 deeply immersed. 



0. dolium var. pliopedemontana Sacco, I Moll, terreni 

 Terziarii del Piemonte, pt. 22, 1897, p. 69, from the Upper 

 Pliocene, Astien, at Fossano, is insufficiently described as 

 having more distinct ribs, the columellar teeth quite high, 

 produced towards the aperture. No figure; the reference to 

 ribs is ambiguous in this species. 



The Recent European species of Orcula are mostly well 

 known, and readily distinguishable by external characters, 

 but much remains to be done in systematizing the subspecific 

 forms and determining which have racial value. Some of the 

 Asiatic species, such as scyphus and sirianocoriensis, appear 

 to be more or less heterogeneous aggregates impossible to 

 systematize until a comparative study of the internal struc- 

 ture can be made. 



The species are so connected that no well-defined subgenera 

 can be based on shell-characters. Three sections may be dis- 

 tinguished thus: 



Outer lip reflected: Section Sphyradium 'Ag.' Charp. (in- 

 cluded in paragraphs 7, 8, 10-12 of the key following). 

 Outer lip merely expanded more or less, generally thickened 

 within. 

 Having a series of bristles at the upper third of each 

 whorl (frequently wanting) ; internal lamellae ex 

 tremely broad : Section Pilorcula Germain. 

 Without such bristles: Section Orcula proper. 



