OF ANIMALCULES. 91 



issue from it, they have so strong a resemblance to the 

 genus Monas, that they cannot be distinguished. When 

 they arrive at the size shewn by figures 76, 82, and 

 83, or at about 1-1 700th of an inch in length, their 

 further development may be distinctly traced. In figure 

 76, the creature has just assumed an elliptical form ; 

 when younger it was probably more spherical : at this 

 period of its growth no cilia are to be observed, except 

 when the water has almost evaporated : in figure 82, 

 which is a side view, these become visible, and the crea- 

 ture is seen creeping along a small piece of partially de- 

 composed vegetable : after this it rapidly increases in size, 

 and the front becomes concave, as shewn in figure 83. 

 The lobes next appear, and then their fringe of cilia, while 

 the back becomes more convex : the animalcule has then 

 nearly arrived at maturity, only wanting the smooth 

 proboscis, as shewn in figure 80. Thus w^e complete the 

 cycle of development ; which is as definite and constant 

 as in any of the larger animals. 



Length of full-grown specimens, l-280th of an inch. 

 They are found in various vegetable infusions, and espe- 

 cially in those of hay which have been kept a consider- 

 able time. 



160. KoLPODA cucullulus (Loxodes cucuUulus, E.) The 

 hood-shaped Kolpoda. — A full-grown specimen of this 

 beautiful species is shewn, magnified 380 times, at figure 

 89. Its body is devoid of cilia, excepting the parts ad- 

 jacent the mouth, which are furnished with a row of 

 delicate hairs ; by these the creature procures its food. 



