494 ANIMAL NATURE OF DIATOMEJE. 



evident complication of the process in the second group, 

 proves the like of the apparently simple process of the 

 first. In fact, it is indeed always necessary that the two 

 new lateral valves of the two individuals be organised, 

 even in simple Naviculeae, and the separation of the two 

 pre-existing always precedes the deduplication. It does 

 not, therefore, appear to me that we can entirely agree 

 with Ehrenberg in what he adduces to distinguish the 

 process of deduplication (sdoppiamento) from regeneration 

 and reproduction. We cannot say that anything gives 

 way, where the formation of new valves appears, and 

 that the division is effectuated by that. The division 

 is merely the last stage of the process, and the per- 

 sistence of the two exterior valves does not seem to me 

 sufficient to prove that a total regeneration of the two 

 new individuals has not occurred. Nor can any one 

 prove that a reabsorption of organic substance and a 

 local renewal (ripristinamento) of organisation has not 

 taken place. And since the new parts which make their 

 appearance change the individual essentially, and do not 

 belong at all to its individual growth, as Ehrenberg 

 sagaciously observes, from this it clearly follows that it 

 had previously ceased to enjoy individual life. If I were 

 not afraid of appearing too transcendental, I would com- 

 pare the progressive deduplication (sdoppiamento) in the 

 Diatomeae, with the successive development of the 

 terminal bud {gemma) of the Sertularieae. This unfolds 

 itself (si sdoppid) into two organisms, which, in smaller 

 dimensions, might appear almost equal ; but one of these 

 enjoys an individual life, the other, again, becomes halved 

 (si sdoppid), and so on indefinitely. 



As respects the rank and position to be allowed the 

 Diatomeae in zoological classification, it results from the 

 observations hitherto collected, that nothing positive can 

 be asserted. No one, henceforth, will have a right to 

 contradict the authoritative opinion of Ehrenberg, who 

 ascribes them to the class of Polygastric Infusoria. 



