On Jurassic and Cretaceous fossils from North-East Greenland. 479 



front part of the ventral margin forming a semicircle; the posterior 

 part of the circumference very like the half part of an ellipse. The 

 shell strongly arched in the neighbourhood of the posterior margin, 

 otherwise rather flat. No sinus on the pallia] line. The hinge not 

 observed. 



Height of the cast 28 mm, its length 36 mm and thickness (of a 

 single valve) ca. 7 mm. 



To judge from the right valves the available casts agree very 

 well with Rouillier's above-cited figure. 



Distribution. North -East Greenland: "Kloft I" on Store 

 Koldewey Island (1 spec). At "4. Samkning" also on Store Koldewey 

 Island (1 spec). — On the top of Muschelberg, Hochstetter's Foreland 

 (2 spec). 



Russia: at Kharoschowo. 



50. Cyprina Syssollae Keysehling. 



PI. XXXV, fig. 6. 



1840. Cyprina Syssollae Keyshrmng, Petschora-Land, p. 3(19; PI. 17. figs. 17 — 22. 



The shell rounded-triangular, relatively higher and shorter than 

 in the previous species, fairly Hat. The umbo somewhat in front of 

 the middle, rather prominent. — The front part of the cardinal 

 margin more concave than in the previous species. Lunula not 

 sharply marked off. The surface covered with coarse and fine, 

 concentric striae. 



All the available specimens (casts and imprints) are more or 

 less defective; their form has been partly somewhat altered by pres- 

 sure. The following measurements can be given of an imprint of a 

 right valve somewhat deformed in this way: 



Height 25 mm, length 29 mm and thickness ca. 9 mm. 



Distribution. North-East Greenland: "Kloft I" on Store 

 Koldewey Island (many spec). At "4. Saenkning" on the same 

 island (5 spec). — Top of Muschelberg on Hochstetter's Foreland 

 (1 spec). 



Russia: in deposits with Belemnites Panderianus. 



51. Cyprina cfr. inconspicua Lindstkom. 



18fi5. Cyprina inconspicua Lindstkom, Trias- och Juraforsteningar fran Spetsbergun. 



p. 11; PI. 3, figs. 7—8. 



A cast of a left valve and a second specimen with the greater 

 part of the shell preserved have a great resemblance to this species, 

 but yet differ so much from it, that they must perhaps be referred 

 to another species. 



