PULVINULINA KARSTENI. 323 



Pclvinulina Kaesteni, Sars, 1868. Vidensk.-Selsk. Forhandl. for 1868, p. 248. 



— — Brady, 1878. Ann. Mag. Nat. Hist., ser. 5, vol. ii, 



p. 436, pi. xxi, fig. 11. 



— candidula, Schwager, 1883. Palseontogr., vol. xxx, p. 133, pi. xxviii, 



fig. 10. 



— Kaesteni, Brady, 1884. Eeport ' Challenger,' p. 698, pi. cv, 



figs. 8, 9. 



— — — 1887. Journ. E. Micr. Soc, p. 923. 



— — Goes, 1894. K. Sv. Vet.-Ak. Handl., vol. xxv, No. 9, 



p. 97, pi. xvi, fig. 807. 



— — Be Amicis, 1895. Nat. Sicil., ann. xiv, p. 55. 



— — Chapman, 1895. Proceed. Zool. Soc, 1895, p. 43. 



Characters. — Shell many-chambered, compact. Upper (spiral) surface conical, 

 smooth, and free from limbation, Lower surface convex, umbonate ; septa and 

 margin limbate. Periphery slightly lobulate. 



Pulvlnulina Karsteni is the small, comparatively thick, many-chambered 

 modification of the type which seems to find a place between P. Menardii and 

 P. Schreibersii. The wheel-like appearance of the lower surface imparted by the 

 somewhat thickened umbo and slightly limbate sutures and margin (the upper 

 surface retaining the normal smooth condition) is sufficiently characteristic in well- 

 developed specimens. These characters, however, are so often more or less wanting 

 that the species is frequently very difficult to identify. 



Our figured specimen is such as has been recorded (' Phil. Trans.,' vol. civ, 

 Table VII, p. 422), very rare and very small, in the Peterborough fens. 

 Larger specimens occur at the Hunde Islands, in the Arctic region, and these 

 approach closely the varieties met with in the Lias and. Oolite, and these latter 

 pass insensibly into P. elegans, and from that into P. caracolla. 



Occurrence. — Pulvlnulina Karsteni appears to be typically an Arctic form. 

 According to the ' Challenger ' Report it has not been met with south of 

 lat. 38° 34' in the Northern Hemisphere, and in the Southern Hemisphere north 

 of lat. 26° 45'. This is corroborated by the total absence of the species in the 

 gatherings of the ' Gazelle.' Fossil specimens have been recorded from the 

 Neocomian (Bargate Beds) of Surrey, from the Phosphatic Chalk of Taplow, and 

 from the Chalk of Mecklenburg ; from the Eocene (London Clay) ; from the 

 Pliocene of Italy and St. Erth ; the Pleistocene of Italy and Britain. In the 

 Coralline Crag we have one specimen from Tattingstone, zone d. It was recorded 

 in the First Part of the Monograph from the Upper Crag of Southwold. 



42 



