440 Transactions of the Society. 



149. Spirillina Umbata Brady. 



Spirillina Umbata Brady, 1879, Quart. Journ. Micr. Sci., vol. xix. n.s., 



p. 278, pi. viii., fig. 26. 

 Ditto. (Brady) Brady, 1884, Foram. 'Challenger,' p. 632, pi. lxxxv. 



• figs. 18-21. 

 Ditto. (Brady) Siddall, 1886, Proc. Lit. Phil. Soc, Liverpool, vol. xl., 



Appendix, p. 59. 

 Ditto. (Brady) Brady, 1887, Synopsis British Kecent Forarninifera. 



Fossil. Several specimens, which are with some hesitation 

 referred to this species, the matrix which is still adherent to them 

 rendering their precise identification somewhat doubtful. One of 

 the specimens is clearly derived from the limestone of the Mixon 

 Eocks. It has apparently never been recorded previously in the 

 fossil state. 



150. Spirillina margaritifera Williamson. 



Spirillina margaritifera Williamson, 1858, Becent Foram. Gt. Britain, p. 93, 



pi. vii. fig. 204. 

 Ditto. (Williamson) J. Wright, 1886, Proc. Belfast Nat. Field Club, App. 



1885-86, p. 321, pi. xxvi. fig. 12. 

 Ditto. (Williamson) Brady, 1887, Synopsis British Becent Forarninifera. 



Two fossil specimens from opposite Medmerry Farm (north-west 

 corner). The locality of Williamson's specimen is not stated, and it 

 is not clear whether it was a recent specimen or a derived fossil. 

 The species is rare, but widely distributed in the recent state. It 

 occurs in some abundance in coral sands from Macassar. Closely 

 allied forms have been described by Tercjuem from the Eocene of 

 Paris under the name of & nodifera, and it is possible that our 

 specimens are derived from a Tertiary deposit of similar age. 



151. Spirillina selseyensis sp. n. 



(Plate XVIII. figs. 6, 7.) 



Several specimens of fossil origin have been found which are 

 evidently closely allied to S. margaritifera Williamson, but which 

 present well-marked points of distinction. The shell is somewhat 

 concave on the superior side. The sutural lines are strongly 

 limbate as in S. margaritifera, but ' the sutures are connected by 

 shallower intermediate ridges. On the inferior side it is almost 

 flat, though slightly excavated towards the umbilical region. Each 

 whorl bears a series of raised tubercles which, increasing in size 

 with the width of the spiral tube, are set at an angle to the peri- 

 phery of the shell, so as to resemble the spiral twisting of the 

 strands of a rope. Diameter, ■ 25-0 • 3 mm. 



