398 ANIMAL NATURE OF DIATOME^E. 



materials for numerous and valuable observations. It 

 would appear that Kiitzing, anxious to establish the 

 vegetable nature of Diatomeae, designedly passed over 

 this argument, and sought to distract attention by creating 

 new species out of the various forms assumed by JS. stria- 

 tula at successive periods of age and degrees of de- 

 velopment. Such we may suspect to be his S. Pala 

 and S. ovata, as well as the #. ovalis of Brebisson, who, 

 as early as 1835, and not in 1838, had made public his 

 S. biseriata, a name, therefore, which ought to be 

 retained in preference to the later one (S. bifrons) of 

 Ehrenberg. Bailey, too, noted the quick and lively move- 

 ments of S. striatula, and I had frequent opportunities of 

 observing it in our Euganean warm springs. I could 

 compare together living individuals, among which there 

 occurs an indescribable complication of internal structure, 

 and dead skeletons, such as are represented by Kiitzing. 

 Nor can I omit here the 8. gemma, in which Ehrenberg 

 discovered numerous extensible and contractile cirrhi 

 which appeared to serve as organs of motion. It appears 

 that Kiitzing had seen something similar in S. solea, 

 (PL iii, fig. 61, 2.) And in regard to S. gemma we 

 must remember the lateral openings from which, accord- 

 ing to Ehrenberg these cirrhi are protruded; openings 

 which it would seem must exist also in S.fastuosa, and 

 which remind us, also, of those before mentioned iii some 

 species of Epithemia, as the cirrhi remind us of the cilia 

 of E. ciliata (Navicula] of Corda. It appears to me 

 that it is now with Diatomeas as it was with Mollusca 

 down to the time of Cuvier, and that anatomy has to 

 effect the same beneficial revolution in their natural 

 classification, which it produced in the system and 

 nomenclature of Conchylia. 



Kiitzing finally ascribes to the same genus Suriretta, 

 as the last section or sub-genus (Podocystis), that species 

 which I found to be so common in our sea, and which 

 he therefore names adriatica; this association is truly 

 singular, for whilst we see that the second sections are 



