114 HALKYARD, Fossil Foraminifera of the Blue Marl 



2/9. DlSCORJBINA COMPRESSA, sp. IIOV. 



PI. VII, fig. 3. 



Shell compressed, thin, flattened on both surfaces, peri- 

 pheral edge sharp, generally keeled. Test composed of. about 

 sixteen arched chambers. The sutures and spiral line of earlier 

 chambers limbate on superior surface, which is also decorated 

 with scattered tubercles. Inferior surface smooth except for 

 a few tubercles occupying the centre of the disc. Diam. 1.0 

 mm. 



The species is rather rare but is easily distinguished from 

 the other members of the genus. When unaltered by erosion,, 

 etc., the shell is seen to be thin and semi-transparent with com- 

 paratively large pores. In the specimen figured the last cham- 

 ber is fractured. I draw attention to this fact to avoid all 

 possibility of misinterpretation of my drawing. 



(Halkyard's drawing shows a feature which is not referred 

 to in the description but which is certainly one of the most 

 striking points in the species, viz., the prominence of the 

 secondary, or asterigerine, series of chambers which are 

 exposed on the superior surface of the test, but invisible on the 

 inferior, contrary to the usual order of things. It is assumed 

 that the carinate edge marks the inferior face, as in other 

 species.) 



280. DiscoRBiNA globigerinoides, Parker & Jones. 



Discorbina globigerinoides, Parker & Jones, 1865, Phil. Trans.. 



p. 385 & 421, pi. XIX, figs. 7a, b, c. 



Extremely rare. A single well-grown specimen only having 

 been found. 



(The specimen is an infiltrated fossil, and we cannot satisfy 

 ourselves as to its identity.) 



Genus Planorbulina, d'Orbigny. 

 281. Planorbulina mediterranensis, d'Orbigny. 



Planorbulina mediterranensis , d'Orbignv, 1826, Ann. Sci. Nat.,. 



vol. VII, p. 280, pi. XIV, figs. 4-6.' 

 Planorbulina mediterranensis, Brady, 1884, Chall. Rep., vol. 



IX, p. 656, pi. XCII, figs. 1-3. 



Very rare. Two small broken specimens from the upper- 

 part of the Marl. 



