DESCRIPTION OF PLATE IV.

Various species of Living Infusoria, to illustrate the nature of Fossil
Animalcules.

For detailed descriptions, see pages 217-220.

Figs. 1 to 5.-Various kinds of Xanthidia: figs. 2, 3, 4, have been found in a pond on Clapham Common, and fig. 1. living in a pond near Westpoint, United States.

1

6.-Bacillaria vulgaris: of a line in diameter. Pond on Clapham

Common.

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7.-Cocconeis scutellum: in the Baltic:

1

8.-Navicula viridis : of a line. Ponds on Clapham Common.
9.—The same; a side view; showing the currents produced in the
water by the animal when in locomotion.

1

10.-Gaillonella lineata : of a line. Ponds on Clapham Common.

36

1

13.—-Podosphenia gracilis: of a line; attached to a thread of

Calothria, and having by self-division formed a radiating cluster of individuals. Common in the ditches communicating with the Thames, in Battersea-fields.

1

17. A group of the same, living: of a line (Ehrenberg): a piece

20

of Conferva rivularis, beset with these animalcules. The smaller species are E. Westermanni.