Astasiaea.] infusorial animalcules. 189 



of a fixed chfiractcT, sometimes beiug green, at others, a mixture of 

 red and green. This arises, acicording toElirenberg, from the different 

 condition of the ova at different times ; the ova conceal beneath 

 them numerous round granular bodies, supposed to be digestive cells. 

 The thread-like proboscis, which is a prolongation of the upper lip, 

 and rather longer than the body, is so delicate, as to require con- 

 siderable care in investigating it, and being retractile, will often 

 elude observation. A little coloming matter in the water will 

 exhibit this organ in active operation, and it may be distinctly seen 

 in a single animalcule, in a di'ied state, upon a plate of clear glass. 

 The double appearance of the organ in this species has been before 

 noticed. Ehrenberg conjectures that the mii-acle in Egypt, recorded 

 by the great lawgiver of the Jews, of turning the water into blood, 

 might have been effected by the agency of these creatures, or by the 

 Astasia h(ematodes. Figures 71, 72, and 73, represent the creature 

 in different states. In the fii'st, it appears elongated, and currents 

 in the water are shown near the mouth. In the others, the cilia- 

 formed thi'ead-like proboscis is seen. Found in stagnant water, 

 often in great abundance, on the surface of ponds. Length 1 -300th 

 to 1 -240th. 



i-' EuGLENA hyalina. Body extensible in a spindle-shaped manner, with 

 the head attenuated, blunted at the extremity, and two-lipped ; tail 

 short, and somewhat pointed ; colour transparent and whitish, rare. 

 Length l-280th. 



E. deses (^Enchehjsdeses, M.) Body extensible, cylindrical, abruptly 

 rounded at the head, and slightly bi-lipped. Tail very short and 

 pointed ; colour green ; motion a winding and sluggish creeping, 

 never swimming. Found amongst Lemna. Length 1 -240th to 

 1- 760th. 



E. viridis (^Cercaria viridis, M.) Body extensible in a spindle- 

 shaped manner, with the head attenuated and sliort. Tail short, and 

 cone-shaped, not cleft; colour green, excepting the two extremities, 

 which are colourless. The double pointed tail, supposed to have been 

 seen by Leeuwenhoek, Ingenhousz Midler, Schrank, and Nitzsch, 

 does not exist. The colour of the eye is often pale red, when the 

 creature is young, so that it may be easily mistaken for the Astasia 

 viridis or Jlouas deses. When diied on glass, the eye seldom retains 



