THE LOWER FORMS OF LIFE. 41 



myself with, I hope, exciting sufficient interest to induce some at 

 least to pursue it further. 



Until the last thirty years the Foraminifera were classed as 

 mollusca, and were placed with them in conchological works. In 

 1826 M. D'Orbigny, a celebrated French naturalist, published a mono- 

 graph upon the family, and was the first to bring them into anything 

 like scientific order, but he still regarded them as mollusca. It was 

 in 1835 that Dujardin, to whom we are indebted for many valuable 

 discoveries among the lower forms of life, particularly those assumed 

 by the protoplasm, to which he gave the name of sarcode, turned 

 the attention of naturalists to the fact that the shells of the Forami- 

 nifera, were secreted by the Amoeba. Subsequent investigations by 

 both Continental and British histologists have fully confirmed this 

 discovery, and the works of Williamson and Carpenter, published 

 by the Eay Society, have brought together and added to their own 

 most valuable investigations all that is known up to, I may say, the 

 present day about these most remarkable Protozoons. Other and 

 original investigators have, however, added much to our knowledge 

 of the Foraminifera, among whom Dr. Wallich in this country stands 

 pre-eminent. 



The shells of the Foraminifera have three distinct types of texture. 

 They are for the most part calcareous ; in fact, Dr. Carpenter thinks 

 they may all be considered as essentially formed of calcareous 

 matter. Their appearance, however, is that of three distinct types 

 first, those in which the shell has the external character and 

 glossy look of porcelain ; secondly, those in which it has a hyaline 

 or glassy appearance ; and thirdly, those in which it is formed of 

 sandy particles, which are agglutinated together by a peculiar 

 secretion from the animal, and into the composition of which some, 

 but little, calcareous matter enters. 



The shells which exhibit these different kinds of texture are not 

 divided into groups by reason of their texture. In fact, many of 

 them are partly hyaline and partly porcelanous, or they may be the 

 former when young (Fig. 56, p. 42), and the latter when old (Fig. 55, 

 p. 42). They may be sandy in texture, as in Figs. 43, 57, and 63 

 (p. 42), but there are porcelanous and hyaline shells of the same 

 shape, and in the samegenus, as the spiral shown at Fig. 63 (p. 42). 

 In Figs. 51-54 (p. 42), the texture is what is called sub-hyaline, 

 that is, having a tendency to the porcelain form, which in Fig. 54 

 (p. 42) is seen in all parts of the shell, except the ridge and anterior 

 portion of the segments. 



I have said that the creature that forms these shells is the 

 Amoeba. This is proved by dissolving the shell in weak acid, when 

 its occupant is found to be a cast of the shell, and to be nothing 



