260 MR. P. CH1PMAN ON SOME OP THE [May I9OO, 



face ; consisting of a coiled tube, which is reniform in section 

 owing to the inner surface of each whorl being impressed, as it 

 were, against the rounded edge of the previous whorl ; usually 

 having four turns to the whole coil, but sometimes as many as 

 five or even six. The coiled tubular shell often commences with a 

 spherical chamber, which sometimes appears to be partly divided 

 from the rest of the shell. In places the shell-wall is seen to be 

 finely perforate. Average diameter = yi-^ inch. 



The above form differs materially from the well-known species 

 Sp. vivipara of Ehrenberg * in having a concavo-convex form of test. 

 The tube forming the coils of the disc is also more inflated than in 

 Sp. vivipara, the Cambrian examples showing the tube to be higher 

 than broad in vertical section. 



Another species, Sp. obconica of H. B. Brady, 2 possesses the concave 

 feature of the disc, but it is invariably ovoid in outline. 



As regards the number of whorls, the manner in which the 

 coils are enwrapped, and the presence of a conspicuous primordial 

 chamber, we can compare the Cornuspira crassa of Zwingli & 

 Kiibler, 3 which appears to be a true Spirillina, from the Callovian 

 beds of the Swiss Jurassic. 



The Spirillince which occur in the Cambrian limestone of the 

 Malverns are in a very good state of preservation, considering the 

 fragility of the test. Where there are valves of molluscs cut 

 through in section, they are seen to be filled, in many cases, with 

 the tests of SpnrilUnce crowded together, to the exclusion of other 

 material. 



The genus Spirillina appears to have been hitherto unknown from 

 beds older than the Jurassic. At the present day the genus is 

 characteristic of fairly shallow and muddy deposits, or of areas 

 where calcareous accumulations are sparingly present. 



Note on some of the Earliest-known Foraminifera. 



The oldest foraminifera of which we have any record are perhaps 

 those which have been figured and described by Dr. L. Cayeux 4 

 from quart/ites and phthanites of pre-Cambrian age in Britanny. 

 These bodies are subspherical or globular, and conjoined in many 

 instances ; they bear upon their surfaces blunt spines or pro- 

 cesses, and their walls are finely perforate. Their excessively 

 minute size, however, renders it very difficult to say with certainty 

 that they belong to this particular group of organisms, for the 

 largest of the chambers measure only 10 p (t^ inch) in diameter. 



1 Abhandl. k. Preuss. Akad. Wissensch. Berlin, 1841, p. 443 & pi. iii, fig. 41. 



2 Quart Journ. Micr. Sci. vol. xix (1879) p. 279 & pi. viii, figs. 27 a, b; see 

 also Chall. Rep. vol. ix (1884) p. 630 & pi. lxxxv, figs. 6 & 7. 



3 ' Forain. d. schweiz. Jura' Winterthur, 1870, p. 19 & pi. ii, fig. 2 (Callovien) ; 

 see also Jones, Quart. Journ. Geol. Soc. vol. xl (1884) p. 770 & pi. xxxiv, fig. 13. 



4 ' Sur la Presence de Restesde Foraminiferesdansles Terrains precambriens 

 de Bretagne' Ann. Soc. Geol. Nord, vol. xxii (1894) pp. 116-19. 



