PROTOZOA. 267 



are given out, now in one part and now in another, per- 

 fectly transparent 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 Amoeba 

 there occur, besides the granules, clear spaces with fluid 

 contents, which are sometimes unchangeable in form, and 

 sometimes exhibit rhythmical contractions." 



Allied to the preceding is the very curious Acineta of 

 Ehrenberg, Actinophrys sol, "sun-animalcule." This crea- 

 ture consists of a jelly-like contractile substance, or sarcode, 

 with tentacular filaments, radiating from the central mass, 

 in such a manner as to have suggested the name for the 

 species. It abounds in pools, where Desmidiacece are found, 

 in many parts of Dorsetshire ; they are ravenous feeders, 

 not only upon the Desmidiacece, but also upon all kinds of 

 minute spores and animalcules. 



It was on examining some beautiful Desmidiacece that 

 my attention was arrested by the curious appearance of 

 two or three very small Actinophrys floating very lightly 

 upon the surface of the water, in the form of a ball, with 

 their delicate tentacular filaments perfectly erect all over 

 their bodies; in fact, they seemed to be floating upon 

 these delicate filaments. 1 



The most beautiful forms of the Rhizopoda are found 

 among those possessing a calcareous covering, as the 

 Polythamia, Rosalina, Faujasina, &c. ; their systematic 

 arrangement are founded upon their shells, which exhibit 

 a most beautiful diversity in form. Out of these forms, 

 it would appear, that the labours of various natural- 

 ists in the last hundred years have made known nearly 

 2,000 species of recent and fossil Foraminifera ; and al- 

 though 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 

 inquiry. 



Dr. Schultze acknowledges the difficulties attending 

 the study of the Rhizopoda, and insists, very properly, 

 upon the necessity of viewing them in all positions, 



(1) See Notes on Freshwater Infusoria, by H. J. Carter, Esq. Ann. Nat. JHist, 

 August, 1856. 



