Yol. 50.] MR. F. CHAPMAN ON THE BARGATE REDS OF SURREY. 711 



76. Vaginulina neocomiana, sp. nov. (PI. XXXIV. figs. 10 a, b, 



11.) 



Test elongate ; slightly incurved in the first third of the test, and 

 recurved from a third above the commencement to the terminal 

 chamber. Segments numerous (eight in the full-grown individual) ; 

 the primordial chamber circular and more or less inflated, following 

 which the chambers are compressed and typically Vaginuline ; but 

 later on they assume the character of Marginuline segments, since 

 they are subtriangular in section, and terminate in a marginal neck. 

 Towards the back of the test on each side is a marginal keel, whilst 

 the back itself is also sharp. Sutures well marked, especially in the 

 larger and well-grown examples, which have the later chambers 

 tending to separate one from the other. Surface of the test longi- 

 tudinally striated with fine costae. Length of largest specimen 

 -gL inch (0-9 mm.). 1 



Seven specimens, some fragmentary, from the Pebble-beds, 

 Littleton. 



Cristellaria, Lamarck. 



77. Cristellaria tricarinella, Reuss. 



G. tricarinella, Reuss, Sitzungsb. Akad. Wissensch. Wien, vol. xlvi. 

 (1862) p. 68, pi. vii. fig. 9. 



G. truncana, Giimbel, Abhandl. bayer. Akad. Wissensch. 2te CI. 

 vol. x. (1868) p. 639, pi. i. fig. 68 a, b. 



C. tricarinella, Brady, ' Challenger ' Rep. vol. ix. (1884) p. 540, 

 pi. lxviii. figs. 3, 4. 



0. tricarinella is somewhat closely related to certain forms of 

 Vaginulina, but although the sides of the test are nearly flat, it 

 commences with a distinct spiral growth. Reuss records this species 

 from the Hils-Thon and Speeton Clay of North Germany, and 

 Giimbel obtained his specimens from the Xummulitic marl of the 

 Xressenberg, Bavaria. Its occurrence as a recent form is noted 

 by Dr. Brady from the Pacific, at depths of from 95-155 fathoms. 



One specimen from the Pebble-beds, Littleton, and one from the 

 Pebble-beds, Halfpenny Lane, Chilworth. 



78. Cristellaria vestita, Berthelin. 



G. vestita, Berthelin, Mem. Soc. geol. Prance, ser. 3, vol. i. (1880) 

 no. 5, p. 55, pi. iii. fig. 22. 



This pretty costate form is allied to G. italica (Defrance) in out- 

 line, but differs in the ornamentation of the test. It was described 

 from the Gault of Prance, and is also known from Folkestone. 2 



Two specimens from the Pebble-beds, Littleton. 



1 Several of Terquem's Jurassic species are somewhat related to this form, 

 especially Marginulina h?/brida(' Foraxa. du Lias,' 5me Mem., Metz, 1866, p. 430, 

 pi. xvii. figs. 9 a, b, c), except that the latter has a Cristellarian commencement. 

 Also Vaginulina linearis (Montagu) resembles the above form, but differs 

 materially in having no extreme form of Marginuline neck. 



2 Author's MS. 



