Recent and Fossil Foraminifera. 431 



the form which Williamson described as a variety of P. lactea, 

 we are justified in suppressing d'Orbigny's species, and raising 

 Williamson's variety to specific rank as P. oblonga, a definite type. 



122. Polymorphina concava Williamson. 

 (Plate XVII fig. 6.) 



Polymorphina lactea var. concava, Williamson, 1858, Kec. Foram. Gt. Britain, 



p. 72, pi. vi. figs. 151, 152. 

 Polymorphina concava (Williamson) Brady, Parker and Jones, 1870, Trans. 



Linn. Soc. Lond , vol. xxvii. p. 236, pi. xl. figs. 22 a, b. 

 Ditto. (Williamson) Brady, 1887, Synopsis British Recent Foraminifera. 

 Polymorphina lactea var. concava (Williamson) Sidebottom, 1907, Mem. Lit. 



and Phil. Soj. Manchester, vol. li. pt. 3, p. 14, pi. iii. figs. 8, 9. 



One perfect, recent specimen, unattached. This pretty little 

 Foraminifer is of very infrequent occurrence under any circum- 

 stances, and especially so in shore gatherings. Sidebottom (supra) 

 has written at some length upon the peculiar features of this species. 



123. Polymorphina gibba d'Orbigny. 



Polymorphina (Globulina) gibba d'Orbigny, 1826, Ann. Sci. Nat., vol. vii. 



p. 266, No. 20 ; Modele No. 63. 

 Polymorphina gibba (d'Orbigny) Brady, Parker, and Jones, 1870, Trans. Linn. 



Soc." Lond., vol. xxvii. p. 216, pi. xxxix. fig. 2 a-cl. 

 Ditto. (d'Orbigny) Brady, 1881, Foram. 'Challenger,' p. 561, pi. lxxi. fig. 



12 a, b. 

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



Fossil and recent. Very common, the fossil specimens espe- 

 cially abundant, and presenting the greatest possible variety of 

 form, from the perfectly globular to compressed specimens hardly 

 separable from P. lactea. The fossils are evidently derived from 

 a number of different sources ; many of them show signs of con- 

 siderable wear and weathering. It will be observed later that this 

 is one of the commonest Foraminifera in the Bracklesham clays of 

 the artesian well boring, to be considered at a future date. 



124. Polymorphina sororia, Reuss. 



Polymorphic! ('ruff 'din a) sororia Reuss, 1862, Bull. Acad. Roy. Belg., ser 2, 



vol. xv. p. 121, pi. ii. figs. 25-29. 

 Ditto. Reuss, 1870, Sitz. k. Akacl. Wiss. Wien, vol. Ixii. p. 487, No. 9 ; von 



Schlicht, 1870, Foram. Pietzpuhl, pi. xxvi. figs. 4-12, 16, 18. 

 Polymorphina sororia (Reuss) Brady, 1884, Foram. 'Challenger,' p. 562, 



pi. lxxi. figs. 15, 16. 

 Ditto. (Reuss) Brady, 1887, Synopsis British Recent Foraminifera. 



Fossil. This type is with difficulty separable from P. lactea, 

 from which it is differentiated merely by its elongated sub-fusiform 

 shape. 



