EXPLANATION OF PLATE 9.

FIG.

A. Textularia rugosa, Reuss sp. (after Brady).

× 13.

× 16.

B. T. complanata, Reuss sp. (after Chapman). C. Cuneolina pavonia, D'Orbigny. c = peripheral face view, showing arrangement of suture lines. Magnified.

D. Verneuilina spinulosa, Reuss (after Brady).

× 40.

× 30.
× 10.

E. Tritaxia tricarinata, Reuss (Gault specimen, after Chapman). × 24.
F. Chrysalidina dimorpha, Brady (after Millett).
G. Bigenerina capreolus, D'Orbigny (after Brady).
H. B. (Siphogenerina) Schlumbergeri, Millett. A specimen viewed
by transmitted light, to show internal arrangement.

× 50.

× 30.

× 40.

I. Pavonina flabelliformis, D'Orbigny (after Brady).
J. Spiroplecta annectens, Parker and Jones sp. (after Brady).
K. Gaudryina rugosa, D'Orbigny (Tertiary specimen, after Hantken).
× 20.

L. Valvulina palæotrochus, Ehrenberg sp. Carboniferous limestone, specimen (after Brady). × 24.

M. Clavulina communis, D'Orbigny (after Brady). M, lateral aspect, × 30; m, mouth of a larger specimen, × 22.

N. Bulimina Presli, Reuss (a Gault specimen, after Chapman).

O. Virgulina Schreibersiana, Czjzek (after Brady).

* 30.

× 60.

P. Bifarina porrecta, Brady sp. (after Millett).

× 60.

Q. Bolivina textilarioides, Reuss (after Brady).

x 55.

S. Pleurostomella subnodosa, Reuss (after Brady).

x 37.

T. Cassidulina calabra, Seguenza (after Brady). × 37.
U. C. (Orthoplecta) clavata, Brady. × 56.

V. Ehrenbergina pupa, D'Orbigny (after Brady).

× 42.

and off Kandavu, Fiji Islands, 610 fathoms. The writer has recently met with it in the dredgings made by Prof. David round Funafuti, Ellice Islands, at 50 to 60 fathoms. Upper Miocene and Recent. (Plate 9, fig. T.)

SUB-GENUS Orthoplecta, BRADY.

In this genus there is no coiling of the test, but the segments are otherwise arranged, as in Cassidulina. It bears the same relation to the type-form as Nodosaria does to Cristellaria. Recent.

EXAMPLE.-C. (Orthoplecta) clavata, Brady, 'Rep. "Chall."' vol. ix. 1884, p. 432, pl. cxiii. fig. 9.

This interesting but rare form was originally found at Nares Harbour, Admiralty Islands, 17 fathoms. The writer has since obtained it from the Funafuti dredgings at 50 to 60 fathoms. Recent. (Plate 9, fig. U.)

GENUS Ehrenbergina, REUSS.

Test biserial, broad, arched on the dorsal side; general form that of an unfolded and uncoiled Cassidulina. Lower Cretaceous to Recent.

EXAMPLE.-E. pupa, D'Orbigny sp. (Cassidulina), 'Foram. Amér. Mérid.' 1839, p. 57, pl. vii. figs. 21-23.

This is a smooth-tested form of the above genus. Other species bear numerous spines as in Mimosina, notably Ehrenbergina serrata and E. hystrix. The author has recorded it from the Aptian beds of Surrey. Lower Cretaceous to Recent. (Plate 9, fig. V.)

CHAPTER XII

THE FAMILY CHEILOSTOMELLIDE

ONLY four genera are at present included in this family-namely, Ellipsoidina, Cheilostomella, Seabrookia, and Allomorphina.

The test is always calcareous, usually thin, and finely perforate. The segments, of which there are always more than one, are arranged either successively along an axis, placed alternately to one another at either end of the test, or grouped in cycles of three. The chambers are always more or less embracing. The aperture is either a curved or straight slit at the end or margin of the last segment.

Possibly the best known genus of this family is Cheilostomella, in which the chambers are placed alternately at either end of the long axis of the test. The separate segments are inflated, and the shellwalls of the chambers almost entirely conceal one another by their embracing growth.

In Ellipselina the chambers are entirely embracing, and a solid shelly column runs from the top of one chamber to the top of the succeeding one.

Alomorphint resembles Chelostomella in the alternation of the position of the chambers, but the arrangement is in a cycle of three.