PROTOCOCCUS PLUVIALIS. 553 



as to whether the Protococcus plumalis were allied to the 

 Lion or to the Oak. All our common notions of the 

 two kingdoms being derived from such higher organisms 

 as those, and not from those of the invisible world. 



But the Protococcus is as far from the Lion as it is from 

 the Oak; there are observable in it, properties which would 

 appear to find their analogies only in certain animals or 

 certain plants, viz., among the Infusoria or the Algae. 



Of the latter, again, the more highly organised, multi- 

 cellular forms must be excluded, these belonging mani- 

 festly to the Vegetable Kingdom. A Fucus, for instance, 

 is incontestably differently constructed from a Protococcus 

 cell. It is only the so-called unicellular Alga? of Nageli, 

 the Palmelleae and Diatomaceae, about whose proper 

 position there can exist any possible doubt. 



In the same way, of Infusoria, next to the Rotifera, all 

 those among the Polygastrica of Ehr. must be excluded, 

 which have distinctly a mouth and anus, as well as an 

 intestinal canal, or at least an oesophagus. With respect 

 to these, also, no doubt can arise as to their proper 

 position in the scale of animated nature. 



Besides these, however, there are Infusoria, having 

 neither intestine nor anus, which do not take in any solid 

 nutriment, and in which the existence of a mouth is not 

 demonstrable by direct observation, and can only be sur- 

 mised from analogy. These constitute the division of the 

 Anentera, Ehr., Astoma, v. Siebold. With respect to 

 these, it may certainly be reasonably questioned, whether 

 an organism should be more properly referred to this 

 division of the Infusoria, or to the Algae just mentioned. 

 It cannot but be doubtful whether a given creature is to 

 be regarded as belonging to the Monadina, Cryptomo- 

 nadina, Fblvocina, Astasiea, Bacillarice, Amceba, Arcel- 

 lina, &c., or whether it should not be referred to the 

 Cryptococcacece, Protococcacea, Palmellece, Desmidica, 

 and Diatomacece. It may even be questioned, whether 

 some of these natural families be not more nearly related 

 with some families in the other kingdom, than with their 



