224 DESCRIPTION OF [Poly gastric a. 



most decisive characters of animal natxu'e ; but I have elsewhere 

 proved, in the most satisfactory manner, that self-division is very- 

 common, both in the lowest plants as well as in the elementary 

 organs of the more highly developed ones. The little vesicles 

 endowed with molecular motion, seen in the genus Euastrum are 

 completely identical with those observed in Closterium and the Con- 

 ferva, and. I see no good reason why Closterium should not be placed 

 near JEuastrum. The green corpuscles observed withia the cells of 

 most of the Desmidiacea are similar to the green corj^uscles found in 

 the cells of the Conferva ; and though Ehrenberg may consider them 

 as ova, I have observed their develojjment in spores, and in several 

 genera have distiactly seen that they contained amylum, and some- 

 times that they were even entirely composed of it. 



" The second section of the BaciUaria includes the true BaciUaria, 

 and are indicated by the term Kaviculacea ; here are to be found 

 those numerous forms, which, from their occuiTence in a fossil state, 

 have lately given rise to such a great degree of interest, and which 

 Ehrenberg, and many other naturalists, regard as undoubtedly 

 belonging to the animal kingdom. 



'* The reasons adduced for such belief, however, are so weak, that 

 the conclusions deduced from them are yet, for the most pai't, very 

 doubtful. 



"The movement of the BaciUaria, however free it may be, is by 

 no means so free and active as that of the spores of the AJgae and the 

 spennatic animalcules, which are plants, or at least parts of plants, 

 and the motion is no very positive ground for the behef of their animal 

 condition. The common mode of propagation, seen in BaciUaria, is 

 that of self-division, which is also proper to the cells of the higher 

 plants ; the increase by spores or ova ensues but rarely. The fonn, 

 structure, and especially the habitus of the BaciUaria are evidently 

 of that kind to lead one to consider them as plants ; but the following 

 circumstance, which is of very considerable interest, militates against 

 it. In many Nmiculm, it is observed that the molecules, such as of 

 indigo or carmine, &c., in the same solution, that may come into 

 contact with the surface of the body of the creature, are immediately 

 set in motion, and often run along with considerable rapidity by the 

 side of the body, and even turn and run in an opposite direction. 



