294 
THE GEOLOGIST. 
lata is very abundant in the Gault, Upper Greensand, Chalk-marl, and Chalk. Its oc- 
currence in the red chalk of Yorkshire is noticed in the 'Geologist,' 1859, p. 275 ; and 
1860, p. 420. 
Fig. 3. Textularia. TEOcnrs, D'Orhigny. 
One of the most symmetrical of the Textulariae,* and found chiefly in the Chalk, ac 
compauied with T. turris and many other varieties. 
Fig. 4, 5. Textularia agglutixans, D'OrUgny, var. 
The Tcxtularise are so variable in their growth, formiug vesicular or flattened cham- 
bers, and arranging them sometimes so regularly and at other times with such a want 
of neatness, that there may be almost as many names for them as there are individuals. 
I'ig. 4 and 5 are examples of this. Badly grown specimens of the typical form known 
as T. agglutinans, they form links with the variety named T. fieda and many others. 
These Textularise are extremely common iu the Gault, Chalk-marl, and Chalk. 
Fig. 6. Textularia Baudouineana, HOrhigny. 
This is another common form of Textularia, more symmetrical in outline and in the 
setting on of its compressed chambers, than Fig. 4 and 5. It can be scarcely, if at all, 
distinguished from a well-grown T. sagittula, Defrance. 
Fig. 7, 8. Planorbulina ammoxoides, Reuss, sp. 
Most of the Planorbuliuse, especially the larger forms, live in the shallower sea-zones, 
chiefly among seaweeds ; but in deep water they pass into smaller and more compact 
varieties, such as Fig. 7 and 8. These subnautiloid forms are common in some of the 
Jurassic clays and in the Gault, Chalk-marl, and Chalk, and abound iu the existing seas 
at depths greater than 100 fathoms. 
Fig. 9-11. PuLYiNULiNAf umbtlicata, D'Orlifjny, sp. 
This belongs to a large family of Rotaline Foraniinifera, which group themselves 
around Pulvinulina repanda, Fichtel and Moll., sp. It belongs more especially to the 
subgroup of which P. Menardii is the type. This attains its best growth at about 100 
fathoms in the existing seas, but lives well at abyssal depths, even at more than two 
miles depth ; whilst, on the contrary, in shallow water it degenerates iuto bizarre varie- 
ties. D'Orbigriy's Rotalia Micheliana and R. crassa, figured on the same plate (Mem. 
Soc. Geol. France, iv. pi. 3) from which Fig. 9-11 have been copied, are also vai'ieties 
of Pulvinulina Menardii. These are all three found in existing seas under the condi- 
tions mentioned above, and are abundant in the Gault, Chalk-mt^rl, and Chalk. 
Fig. 12. Lituola nautiloidea, Lamarck. 
This is the elongate form of Lituola, the short condition of which is more or less nau- 
tiloid in shape. Lituola has vctt variable states of growth according to its place of 
living, and is often attached to shells, seaweeds, etc. ; it has therefore many varieties, re- 
cent and fossil. 
Fig. 13. Marginulina trilobata, D' OrUgny. 
Marginulinse are Cristellarisc with short chambers, arranged without coiling, except 
at the commencement. They are present wherever Cristellarise abound. 
Fig, 14, 15. Lingulit^a carixata, jyOrhigny. 
This is a smooth compressed Nodosaria, the gradation from cylindrical to flattened 
forms being extremely gentle iu numerous intermediate forms ; and further, these flattened 
Nodosarise, by the backward growth of the sides of the chambers and fuilher compression, 
gradually pass into Frondicularia ; see Quart. Journ. Geol. Soc. xvi. p. 453, pi. 19. 
Lingulince are not very common in the Cretaceous formations. The specimen figured 
(PI. XV., Fig. 14, 15) is a remarkably fine individual (magnified six times) from the Chalk 
of Gravesend. Fig. 14 shows the slit-like aperture. 
* See " Memoir on Textularise," by Messrs. Parker and Jones, Annals of Nat. Hist. 
February 1863. 
t For the description of the genera Pulvinulina and Planorbulina, see Carpenter's 
' Introduction to the Study of Foraniinifera' (Ray Society), 1862, p. 200, 210, etc. 
