4(50 J. P. J. Bavn. 



17. Aucella piriformis Lahusen, emend. A. P. Pavi.ow. 

 PI. XXXII. figs. 11 and 12. 



1874. Aucella concentrica var. rugosa Keys. ; Toula (pars), Kuhn-Insel, p. 503; 



PI. 2, fig. 2. 

 1881. — Keyserlingiana Thautsch., forma majuscula Tullberg, Aucellen-Schich 



ten Novaja-Semljas, p. 23; PI. 2, figs. 9-12. 

 '.'1884. — concentrica Fisch. var.; White, On Mesozoic Fossils, p. 13; PI. 6, 



figs. 6—7. 

 1888. — sublaevis (Keys.) Lahus.; Nikitin, Periode cretacee Russie centrale, 



p. 74; PI. 2, figs. 13-14. 

 1888. — piriformis Lahusen, Ueber die russischcn Aucellen, p. 42 J PI. 5, figs. 3 — 7. 

 1900. — Keyserlingi Lah.; Woli.emann, Bivalven u. Gastrop. des deutschen u. 



holland. Neocoms, p. 56; PI. 2, figs. 0—9. 



1907. — piriformis Lahus.; Pavlow, Enchainement etc., p. 63; PI. 5, figs. 20— 22. 



1908. sublaevis Keys.; Sokoi.ow, Aucellen vom Timan etc., p. 22; PI. 3, 



figs. 3—5. 



A fairly large number of specimens of A. piriformis were found 

 in a reddish brown limestone in Aucellabjerget on Store Koldewey 

 Island along with .4. crassicollis. The rock consists for the most 

 part of more or less well-preserved Aucella shells; it farther contains 

 a number of fragments of gneiss, as also small Hakes of white and 

 black mica, garnet etc. Secondary are here and there secreted groups 

 of calcite. 



The left valve short, pyriform, rather oblique, strongly inflated, 

 thickest about the middle; the beak short, curved inwards and 

 somewhat forwards; the surface covered with regular, fairly sharp, 

 concentric folds. — The right valve obliquely oviform, evenly but 

 much less strongly arched than the left valve; its greatest thickness 

 lying above the middle and from here lessening evenly towards the 

 ventral margin; the beak pointed, somewhat prominent and inclined 

 forwards; the surface like that of the left valve. 



Right valve: length liSinm, breadth 32 mm and thickness 1(5 mm; 

 angle at the beak ca. 70°. 



The specimens seem to agree exceedingly well with Toula 's form 

 from Kuhn Island. 



Distribution. North-East Greenland: along with A. crassicol- 

 lis in Aucellabjerget on Store Koldewey (many spec). — Kuhn Island 

 (2nd German North Pole Expedition). 



Nova Zembla: in the Aucella deposits. 



Russia: the species has a wide distribution in deposits belonging 

 to the zone with Polyptychites polyptychic. 



Germany: Neocomian beds. 



Alaska (?): Neocomian beds. 



