133 On Fossil Infusoria, discovered in Peat-earth, 



tures are at times mentioned as plants, at times as animals, and indeed 

 under quite different denominations.* 



" Morren, in the highly important memoir on the Closteri(S,f has very 

 fully treated the question, whether they should, be arranged with animals 

 or vegetables ; he succeeded by employing very high magnifying powers, 

 in showing that those red and very movable little points discovered by 

 Ehrenberg at the ends of these beings, were nothing else than minute, 

 vesicles which afterwards change into new individuals. Tt was these 

 movable, and as it were, oscillating points, which were considered as or- 

 gans of motion, and appeared to justify the placing of the ClostericB 

 among animals, which, however, at present, after Morren's discovery, falls 

 to the ground. Besides the occurrence of these self-moving propagula in 

 the interior of the Closterics, Morren has observed a formation of fruit by 

 conjugation, quite similar to the mode of formation of the fruit in the 

 ConjugatcB,\ and besides this there also takes place an increase of the 

 Closteri(B by separation. 



"The siliceous envelop which surrounds the Closterice^ as well as all 

 other Bacillarics , is regarded by Morren as a formation analogous to the so 

 called cuticula of plants, a fact which is capable of confirmation only in 

 certain relations ; for in the perfect plants this fine plate of silica lies in 

 the substance of the cuticula, and is only separated from this by the de- 

 struction of the organic parts. Besides this siliceous envelop, Morren 

 supposes the existence of two other distinct membranes, which form the 

 cuticles of the Closterice, and inclose the green substance ; he however 

 remarks, that ihey only become evident upon the metamorphosis of the 

 plant. I consider the inner pellicle to be the analogue of the inner en- 

 velop which is found in the members of Confervse when their spores are 

 ripened, or they begin to increase in any other manner, as for instance, 

 by excrescence and separation. Morren thinks it possible to explain the 

 motion of the ClostericB by the action of opposite electricities. The au- 

 thor also gives a very complete description, accompanied by drawings, of 

 the very manifold forms which the ClostericB exhibit at different periods ; 

 and by this he shows, how at least six of the new 'species of the genus 

 Closterium, described by Ehrenberg, belong to one and the same species. 



"De Brebisson§ also made observations oTi the enigmatical Diatojncs, 

 in order to decide the question, whether tliey should be classed with ani- 



* I ara sorry to say, that these contradictions must also occnr in this year's report, 

 as I do not think Ehrenberg's view as to the animal nature of the BaciUariaweak- 

 ened by the reasons here stated. — Wiegw.ann. 



t Sur les Clostdries, Jinn, des Scienc. JYat.', Vol. I, p. 274. 



I The same observation had been made by Corda. — Also by Ehrenberg in 

 1834. — Wiegmmin. 



§ Observations sur les Diatomees. L'Institut de 1836, p. 378. Ann. des Scienc. 

 Nat., 1836, II, p. 248. 



