DISTGECHIA. 335 



lamella reaching to the plane of the peristome. These two 

 lamellae are resorbed above the penult, whorl, 'but vestiges of 

 them are visible throughout the extent of the axis. Length 

 7.5, diam. 2.5 mm. (Girard). 



Pyrgina umbilicata GREEF, Zool. Anzeiger 1882, p. 518; 

 Sitzber. Marburg 1884, p. 52. GIRARD, Jornal iii, p. 108, pi. 

 1, f. 19, 20. 



Island of St. Thome, at Roca Monte Cafe, 800-900 meters 

 above the sea (Greef) ; Palanca (Newton). 



Six individuals were taken by Mr. Greef, seven by Mr. F. 

 Newton, the latter all dead and without cuticle. It seems to 

 be very rare. 



Genus DISTCECHIA Crosse. 



Distwchia CROSSE, Journ. de Conchyl. for 1890, p. 164, for 

 Cylindrella parisiensis Desh (1890). "Distactria Cossmann 

 Mss.," HARRIS & BURROWS, The Eocene and Oligocene Beds 

 of the Paris Basin, pp. 100, 114 (Sept. 23, 1891) . Spartina 

 HARRIS & BURROWS, t. c., pp. 100, 113. Cylindrella DESK., 

 Anim. sans Vert, du Bassin de Paris, ii, 872. COSSMANN; 

 Ann. Soc. Roy. Malac. de Belgique, xxiv, 1889, p. 358. 



Shell tapering-cylindric, with an obtuse, smooth apex, usu- 

 ally lost in mature shells; longitudinally ribbed; last whorl 

 with a strong, cord-like basal carina, the base smooth, another 

 keel around the large umbilicus; last whorl 'becoming free in 

 front. Aperture irregularly oval, the outer and basal lips 

 shortly built forward beyond a strong collar-like rib ; inner 

 lip blunt. Axis large and hollow, open below. Cavity of the 

 shell contracted by a thin, spiral lamella above the middle 

 of the axis, extending nearly to the aperture, and within the 

 last whorl there is also a palatal fold and a stout basal fold. 

 Type D. parisiensis Desh., pi. 49, figs. 19-22. 



Distribution : Lowest Eocene of the Paris Basin, at Jon- 

 chery and Chenay. 



This group, based upon a single species, is apparently re- 

 lated to Pyrgina and Thomea of St. Thome, and in a less de- 

 gree to Cceliaxis of South Africa; all having the same gen- 

 eral type of internal armature, of external sculpture, and a 



