40 POPULAR ILLUSTRATIONS OF 



At b an unfortunate diatom has got caught, and it will be noticed 

 that the sarcode is concentrating [around him ; he will speedily be 

 covered in, digested, and his siliceous shield sent forth for the 

 examination of future Grevilles, who, many thousand of years hence, 

 find it in the field of their microscopes. 



In the next chapter I shall deal with those species of Ehizopoda 

 which have the power of forming real shells, of calcareous or excep- 

 tionally of arenaceous texture, which are included under the term 

 Foraminifera organisms of great beauty and absorbing interest. 



CHAPTER IV. 



THE EHIZOPODA (continued). 



THE History of the root-like footed animalculae known as the 

 Ehizopoda, and of which I illustrated the typical forms in my last 

 chapter, is one of surpassing interest to the naturalist, the biologist, 

 and the geologist. More especially is this true with respect to the 

 group to which I will now draw attention. 



THE FORAMINIFERA. 



The simple sarcode Amoeba, as we have seen, have wonderful 

 powers of transformation. They can adopt most singular means for 

 securing their prey, and they are endowed with the power of 

 secreting an outward skeleton or covering to protect them from the 

 numerous dangers to which they must be peculiarly liable. The 

 latter power is exercised in its maximum in the Foraminifera, which 

 are covered with hard calcareous or arenaceous shells, moulded into 

 forms of great beauty, and containing internal arrangements of 

 wonderful complexity. In this group, too, we get out of the minute 

 microscopical series which have hitherto engaged our attention ; for 

 although some of the Foraminifera are as small as any animalcule 

 we have examined, yet they pass upwards gradually from such a size 

 to that of a shilling among living species, but much larger in those 

 which are fossil, while many of the most interesting specimens can 

 be gathered from seaweed or sand by means of a pocket lens only, 

 and placed in our cabinets. The real study of the Foraminifera is 

 an extensive one, for even Carpenter's splendid work, published by 

 the Eay Society, is only very properly termed an " Introduction to 

 the Study of Foraminifera." I cannot pretend, however, in this 

 little work to go at great length into the subject, but shall content 



