306 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 4, 



124—126. These are varieties of Botalia (Calcarina) Spengleri, 

 Gmelin. 



126. Calcarina ewcentrica. This is a peculiar, and not previously 

 described variety of G. Spengleri, attaining a relatively large 

 size (that of half a mustard-seed). It commences its growth as 

 a little Botalia, scarcely distinguishable from R. armata, which 

 is a small variety of C. Spengleri. Each cell grows out into a 

 projecting angle, giving a dentate margin to the shell. At first 

 spirally discoid, this Calcarina soon begins to grow all on one 

 side, producing a subtriangular or fan-shaped mass ; the apex 

 consisting of the first few spiral chambers ; the base being- 

 notched in outline, and broadening with a cyclical tendency. 

 Beyond this stage a further growth of cells woidd produce a 

 complanate cyclical shell. Planorbulina farcta presents at one 

 stage of its growth a plan of growth like that of C. excentrica, 

 and at a later period such a cylical arrangement as that above 

 referred to. 



127-132. Varieties of Botalia Turbo, D'Orb. 



128. Botalia Turbo, D'Orb. Here represented by B. Patella, Reuss, 

 Denkschr. Akad.Wien, i. pi. 46. f. 22, which is evidently a small 

 form of B. Turbo. 



132. Botalia elegans, D'Orb. Anomalina elegans, D'Orb. Ann. Sc. 

 Nat. vii. p. 282, No. 4 ; Modeles, No. 42 ; Bosalina complanata, 

 D'Orb. For. Foss. Vien. pi. 10. f. 13-15. This is a variety of 

 B. Turbo. 



134. Nonionina splmroides, D'Orb. This differs from the other 

 Nonionina; (which are varieties of Polystomella), and indeed it 

 appears to be more nearly related to Globigerina than to Poly- 

 stomella. It has fewer chambers than any common Nonionina, 

 and its low arched aperture is very much wider ; its substance 

 is dense, clear, finely porous, and highly polished (except at 

 the margins of the aperture, which are granular). By these 

 features, and by the setting on of the chambers, it is markedly 

 distinguished from Nonionina, and probably deserves another 

 appellation ; but until its relationship to the deep-sea varieties 

 of Polystomella and to the abyssal species Globigerina and 

 Spliazroidina shall have been worked out more fully, we prefer 

 leaving it with its present name. Large varieties of N. splice- 

 roides occur at great depths (2200 fathoms, Indian Ocean, &c), 

 and often present a want of symmetry in the spiral form. 



135-146. We have shown elsewhere* that the Nonionina; are feebly 

 developed Polystomella?. The varieties here enumerated present 

 a fair example of the increase of complexity in form and struc- 

 ture from N. Scapha to P. crispa. Carried still further, the 

 peculiarities of structure are exaggerated in the typical P. 

 craticidata. 



* Annals Nat. Hist. 3 ser. vol. v. pp. 101-103. 



