Recent and Fossil Foraminifera. 325 



Polymorphina proNema (d'Orbigny) Brady, Parker and Jonos, 1870, Trans. 



Linn. Soc. Lond , vol. xxvii. p. -225, pi. xxxix. fig. 11. 

 Ditto. (d'Orbigny) Brady, 1870, Edinburgh Catalogue, p. 5. 

 Ditto. (d'Orbigny) Brady, 1884, Foram. ' Challenger,' p. 568, pi. Ixxii. fig. 20, 



pi. lxxiii. fig. 1. 

 Ditto. (d'Orbigny) Brady, 1887, Synopsis British Recent Foraminifera. 

 Ditto. (d'Orbigny) Millett, 1903, Malay Foraminifera, Journ. R. Micr. Soc, 



p. 264. 



Must of our specimens are fossils, and judging from appearances, 

 have been derived from various sources. The species extends back 

 as far as the Lias, and is of world-wide distribution in shallow 

 waters at the present day. The difference between P. problema 

 and P. communis is so slight as scarcely to merit separation. 



358. Polymorphina thouini d'Orbigny. 



Polymorphina thouini d'Orbigny, 1826, Ann. Sci. Nat., vol. vii. p. 265, No. 8; 



Modele, No. 23. 

 Ditto. (d'Orbigny) Brady, Parker and Jones, 1870, Trans. Linn. Soc. Lond., 



vol. xxvii. p. 232, pi. xl. fig. 17. 

 Ditto. (d'Orbigny) Brady, 1884, Foram. ' Challenger,' p. 567, pi. Ixxii. fig. 18. 



A single pyritized fossil, extremely attenuated. According to 

 Brady this is an extremely rare form in the recent condition. As 

 a fossil it occurs in the Eocene of the Paris Basin and subsequently. 



359. Dimorphina longicollis Brady sp. 



(Plate X. fig. 19.) 



Polymorphina lanceolata (pars) Reuss, 1870, Sitz. d. k. Akad. Wiss. Wien, 



vol. lxii. p. 487, No. 12. Von Schlicht, 1870, Foram. Pietzpuhl, 



pi. xxxi. figs. 25-28. 

 Polymorphina longicollis Brady, 1881, Quart. Journ. Micr. Sci., vol. xxi. (n.s.) 



p. 64. 

 Ditto. (Brady) Brady, 1884, Foram. 'Challenger,' p. 572, pi. lxxiii. figs. 



18-19. 



We have a single perfectly preserved fossil specimen which, if 

 Brady's identification of Von Schlicht's figures is correct, is refer- 

 able to Brady's species. Our specimen, as will be seen from the 

 drawing, agrees exactly with Von Schlicht's figure. The surface 

 is quite smooth, whereas tine recent specimens of P. longicollis are 

 always, or nearly always, hispid. 



The question of the necessity of allocating dimorphous types 

 of Polymorphina to the sub-genus Dimorphina is one which is 

 open to very great doubt, but if the sub-genus Dimorphina is to be 

 retained at all it cannot be used to greater advantage than for the 

 recording of such abnormal species as Brady's P. longicollis, which 

 in the dimorphous arrangement of the chambers and produced Uvi- 

 gerine neck differs widely fn »m the accepted definition of Polymor- 

 phina. In the recent state D. longicollis is extremely rare, and 



