132 THE MICROSCOPE. 



fluens, fig. 95, 4, 5, and 6). From the continual changes of shape which 

 it presents, it is honoured with the name of a fabled god, who could be 

 either animal, vegetable, or elemental in his nature. This curious ani- 

 mal presents us with the essential characters of the class Rhizopoda in 

 the simplest form. It appears to be of an exceedingly voracious dis- 

 position, seizing upon any minute aquatic animals or plants that may 

 come in its way, and appropriating them to the nutrition of its own 

 gelatinous body. The mode in which this tender and apparently 

 helpless creature effects this object is very remarkable. The gelatinous 

 matter of which it is composed is capable, as we have seen, of extension 

 in every direction ; accordingly, when the Amceba meets with any 

 thing that it regards as suitable for its support, the substance of the 

 creature, as it were, grows round the object until this is completely 

 enclosed within the body, when it is gradually dissolved. The sub- 

 stances swallowed (if such a term be admissible) by this hungry mass 

 of jelly are often so large, that the creature itself only seems to form a 

 sort of gelatinous coat enclosing its prey. 



Professor Ecker believes in an exact similarity of contractile substance 

 between that of the lower animal forms, such as the Rhizopoda, and 

 that observed in the Hydra. He says : " The properties of this substance, 

 in its simplest form, are seen in the Amoeba, the body of which, as is 

 known, consists of a perfectly transparent albumen-like homogeneous 

 substance, in which nothing but a few granules are imbedded, and 

 which presents no trace of further organisation. This substance is in 

 the highest degree extensible and contractile ; and from the main mass 

 are given out, now in one part and now in another, perfectly transpa- 

 rent rounded processes, which glide over the glass like oil, and are then 

 again merged in a central mass. There is no external membrane. In 

 the body of the Amceba there occur, besides the granules, clear spaces 

 with fluid contents, which are sometimes unchangeable in form, and 

 sometimes exhibit rhythmical contractions." 



Owing to the general similarity which exists apparently throughout 

 the rhizopodous class in the intimate structure of the soft part, their 

 systematic arrangement can only be founded upon their shells, which 

 exhibit an astonishing diversity of form. Out of these forms, it would 

 appear that the labours of various naturalists in the last hundred years 

 have made known nearly 2000 species of recent and fossil Foramini- 

 fera; and although the observations of Dr. Carpenter tend to show 

 the probability that very many of these supposed species are merely 

 varieties, still the number is sufficiently great to prove the importance 

 and interesting nature of the subject. Dr. Schultze acknowledges the 



