16 GUIDE TO THE FOSSIL INVEKTEBRATE ANIMALS. 
Gallery X. Lobosa and Heliozoa skeleton-builders are few, and their 
remains have not been found in any rock. In the Kadiolaria, 
on the other band, tlie large majority form a skeleton, while 
in the Foraminifera there are very few without it well 
developed. These two groups, therefore, are abundantly 
re[>resented in the fossil state. 
Class FORAMINIFERA. 
Table-case Tlio skeleton deposited by the protoplasm of these animals 
Wall-case g^i^^rally consists of carbonate of lime, and is called the shell 
9. 
a b 
Fig. 1. — Living Foraminifera, with extended pseudopodia, some of which 
may be supposed to stretch far beyond the limits of the page, a is an 
Imperforate Foraminifer, Miliola tenera, the nucleus (darkly shaded) 
and the surrounding protoplasm, with its bubbles, prevent the inner 
chambers from being seen. 6 is a Perforate Foraminifer, Eotalia 
vcncta, and shows the pores through which the pseudopodia stretch 
on all sides. Both enlarged 36 diameters, (ilodified from M. S. 
Schultze, 1854.) 
or test. Sometimes, especially in fresh-water species, it consists 
of chitin, a horny substance, and is not found fossil. In 
several a chitinous or thin calcareous coat is strengthened by 
grains of sand or other foreign particles, as is the case of a 
caddis-worm, and some tests of this arenaceous composition 
