298 Messrs. W, K. Parker and T, Rupert Jones on some 



a compressed form, like an arrow-head, to a thickened wedge- 

 like shape. The chambers, which are arranged in two rows, one 

 on each side of the long axis of the shell, and placed alternately, 

 imitate the folds of a braid or plait. Shell generally flattened, 

 but sometimes rounded and conical (as in T. trochus of the 

 Chalk). Chambers more or less depressed and oblong, set on 

 at various angles in different individuals ; in fig. 44 (7'. Sagittula) 

 they are horizontal or transverse, at a right angle to the axis of 

 the shell ; in fig. 45 {T. aciculata) they are at an angle of about 

 60°. These are nearly extreme varieties ; the intermediate gra- 

 dations are numerous and gentle. The thicker varieties have 

 the greater horizontality, and the flatter or thinner forms more 

 angularity in the arrangement of the chambers. In the former 

 the chambers are sometimes globose [T. gibbosa, W Orb.) ; in 

 the latter the edge of the shell becomes a very sharp lamina, 

 sometimes produced, and even jagged or dentate, passing into 

 T. Pala, Czjzek (Haidinger's Abhandl. ii. p. 148. pi. 13. f. 15, 16), 

 and T. carinata,WOYh. (For. Foss. Vienn. pi. 14.* f. 32-34). 

 The aperture is constant in its character of a transverse semi- 

 lunar slit on the inner edge of the chamber (as in Nonionina). 



In the smaller forms of TeMularia, the shell is hyaline and 

 perforated with numerous passages for pseudopodia; but the 

 clear substance of the shell becomes opake as the individuals 

 increase in size, until the original structure is almost lost to 

 view, by foreign particles (such as minute Foraminifera, sand, or 

 prismatic cells of Molluscan shells) becoming agglutinated into 

 the substance of the shell. 



Textularia is represented by a vast variety of forms, most of 

 which are cosmopolitan in their range, and traceable far back in 

 geological age, even to the palaeozoic periods. It is difiicult to 

 divide these varieties into specific groups. The specimens here 

 figured, however diffiering in size and form, occur, with a full 

 complement of intermediate gradations, in the Tertiary beds of 

 Palermo, and are not specifically distinct. Similar forms are 

 common in the British, IMediterranean, Australian, and other 

 sea-sands. The Norwegian individuals are numerous. 



Miliola et Miliolites, Lamarck. PI. X. figs. 28-37. 



24. Biloculina ringens, Lamarck, sp. PI. X. figs. 28-33. 



Miliolites rin(/ensf. Lam. Ann, Mus. v. p. 351 ; ix. pi. 17- f. 1. 

 Biloculina ringens, D'Orb. Ann. Sc. N. vii. p. 297- no. 2. 



* This plate affords an interesting series of these varying forms of Tex- 

 tularia. 



t The specimen figured by Lamarck has lost its outer chamber, the 

 laminar tongue of which remains in place, and appears as an appendage to 

 the shell. 



