Desmidieic.'] inp'usorial animalcut.es. 229 



SeCTIOI^ I. DESJrrDIACEA. 



This is one of tlie sections into which Ehrenberg divides his girat 

 family Bacillaria ; and it agi'ces mainly with the family Desmidiea 

 of other authors. Elu'enberg elevates the Closteria to the rank of a 

 family, — taking position between Vibrionia and Astasicc ; which, 

 however, in the systems of natiu^alists, have only the value of a 

 genus. The alliance set up by Ehrenberg for the Closteria, is now 

 considered imtenable, whilst theu' affinity with BesmidiecB is as 

 generally admitted. We feel ourselves therefore, wan-anted to 

 dej^art so far fi'om following Ehrenberg' s arrangement, as to include 

 Closterkon among the genera of Besmidiece. ; but have already given 

 the characters of the family in its proper place. (See page 179.) 



Eecent researches, and more especially those of Mi-. Ralfs, have 

 so much added to our knowledge of these most beautiful organisms — 

 the Besmidiece, that much of Ehi-enberg's account of them has become 

 obsolete, and cannot be put forward as a fair representation of the 

 present state of science. This circumstance, coupled with that of 

 the almost impossibility of engrafting the newly discovered genera 

 and species into the system of Ehrenberg, — so greatly influenced as 

 that is by his views of the animal organization of the Besmidiece, has 

 induced us to employ the systematic an-angement of those beings, as 

 given by Mr. Ealfs, in his recent admirable Monograph on the 

 " British Desmidicae" it suppljdng, evei-y thing to be desired in pre- 

 senting a concise view of this interesting group. We have freely 

 employed the generic and specific descriptions of that able naturalist. 

 To attempt an independent account, would imply a more intimate 

 and perfect acquaintance with the Besmidiece, than that possessed by 

 one who has so successfully made them a sjDecial study. The present 

 section may be consequently regarded as containing an epitome of 

 Mr. Ealfs Monograph, although the researches of other naturalists 

 are incorporated, and some new genera and species added. 



Those who would acquire a complete knowledge of the Besmidiece, 



