458 •'• P- •!• Ravn. 



ward. Front margin of the valve very steep, the hind margin very 

 llatly curved. Surface of the cast covered with fairly prominent, 

 concentric folds ; no trace of radial sculpture. 



Left valve: length 30mm, breadth 20 mm and thickness 8*5 mm. 

 Angle at the beak ca. (55°. 



Casts of two small (7 — 8 mm long) left valves of an Aucella were 

 found at "Kloft II" on Store Koldewey Island; in these the umbo is 

 pointed and inclined strongly inwards; the surface only has fairly 

 well-marked, concentric folds. These are possibly young specimens 

 of the above species. 



Distribution. North-East Greenland: in boulders near Hare- 

 fjaeld at Danmarks Havn (2 spec). "Kloft I" on Store Koldewey 

 (2 spec.?). 



East Greenland: in Middle Portlandian at Aucella River on 

 Jameson's Land. 



Spitzbergen: in Portlandian. 



King Charles Land: Kimmeridgian — Portlandian. 



Russia: Portlandian. 



England: Portlandian. 



Alaska: Lower Portlandian. 



Mexico: Pavlow notes the species from here with some re- 

 servation. 



14. Aucella tenuistriata Lahusen. 

 PI. XXXII, fig. 7. 



1846. Aucella Pallasii var. polita Keyserling, Petschora-Land, p. 299; PI. 16, fig. 7. 



1888. — — Keys. var. tenuistriala Lahusen, Ueber die russischen Aucellen, 



p. 34; PI. 1, figs. 25-27. 



1901. _ — — - — ; Pompeckj, Aucellen im Kran- 



kischen Jura, p. 25; PI. 4, 

 figs. 5—6. 



1907. — tenuistriata Lahus. var.; Pavi.ow, Enchainement etc., p. 33. 



■The left valve obliquely pyriform, fairly strongly arched, very 

 oblique; umbo benl strongly backwards, concave in front, fairly Hat 

 above; the anterior and ventral margins together forming almost a 

 semicircle; posterior margin somewhat concave. Surface of the cast 

 covered with fine, concentric lines and of still finer radial striae, 

 almost as in A. Bronni. 



Left valve: length 30 mm, breadth 19 mm and thickness ca. 

 (5 mm; angle at the umbo ca. 75°. 



Along with this left valve was also a badly preserved right 

 valve; it is almost completely flat and has the same sculpture as 

 the left valve. 



Distribution. North-East Greenland: in boulders on the 



