4()<S J- P- •'• Ravn. 



The only difference apparent between the specimen described 

 and d'Obbigny's species is, that the posterior end in the Greenland 

 form is somewhat less blunt and a little narrower; the result of the 

 latter is that the cardinal margin is more curved. As there seems 

 lo be complete agreement otherwise, I do not think that there is 

 reason for hesitating to refer this specimen to the species mentioned, 

 especially as 3 other (less well-preserved) specimens agree in this 

 regard with d'Orbigny's description and figures. 



Distribution. North -East Greenland: "Kloft I" (3 spec.) and 

 "Kloft II" (1 spec.) on Store Koldewey Island. — Top of Muschelberg 

 on Hochstetter's Foreland (1 spec). — ? Kuhn Island (2. German 

 North Pole Expedition). 



Russia: North Urals in Oxfordian. 



31. Modiola sp. 



In boulders from the south side of Vesterdalen at Danmarks Hani 

 a couple of specimens were found of a Modiola, which belongs 

 perhaps to a hitherto undescribed species. The material is however 

 too incomplete to permit of a quite certain determination. 



The best preserved valve is 30 — 35 mm long, but little arched, 

 narrow in front and considerably broader behind. The umbo small, 

 lying near the front end. A ridge fairly sharp at first, then more 

 rounded, inns from the umbo obliquely downwards towards the 

 lowermost part of the ventral margin. The surface with comparatively 

 coarse, concentric lines. 



The present form greatly resembles M. Lonsdalei, but is not 

 nearly so much arched as the latter. It is probable, however, that it 

 has originally been somewhat more arched than now, as its flatness 

 is at least in part due to compression. 



32. Modiola hannoverana Sthuckmann ? 



1.S7S. Modiola hannoverana Sthuckmann, Ob. Jura Hannover, p. 84; PI. 2, fig. 1. 

 190(5. — — — ; Bohissjak, Pelecypoden der Jura-Ablagerun- 



gen im europ. Russland, III, p. 9; PI. 2, 



figs. 1—4. 



A couple of specimens of a Modiola greatly resemble this species, 

 but they are so incomplete, that a certain determination is im- 

 possible. 



Shell rather inflated; beaks nearly terminal, triangular-oval, 

 narrowing towards the ventral margin; cardinal margin long and 

 straight; the region in front of the umbo very short, separated from 

 the rest of the valve by a broad furrow. The shell steep in front, 

 sloping more gradually backwards, passing evenly into a relatively 



