42 M. Eh ren berg's Researclies on tlie Infusoria. 



request, which I am sure, before-hand, will be granted, that 

 such parts of Sir Humphry Davy's papers and my own as relate 

 to the subject in question, be considered both as to their letter 

 and spirit, before any conclusion be drawn. 

 Royal Institution, January 9. 1835. 



An Account of Professor Ehre^bero''s more recent Researclies 

 on the Infusoria. With a Plate. 



In some recent numbers of this Journal, we have endeavour- 

 ed to make our readers acquainted with the important researches 

 of Professor Ehrenberg respecting the Infusoria^ chiefly through 

 elaborate analyses of his memoirs by Drs M. Gardiner and 

 Sharpey, in the volumes for 18S2-t53. Since that date, this in- 

 defatigable naturalist has, with unwearied assiduity, been pro- 

 secuting his investigations, and has given an account of them in 

 a folio volume which has been lately published at Berlin.* We 

 shall now endeavour to present our readers with a short epitome 

 of the most important of his additional discoveries. 



This new work is divided into three parts. The first is de- 

 voted to the refutation of the hypothesis which maintains the 

 existence of a primitive organic substance ; the second consists 

 of observations on divers points of the anatomy and physiology 

 of the Infusoria ; and the third contains a description of three 

 new families, thirty-one new genera, and 135 new species of /w- 

 fusor'ia. It is of the second part only that we shall here present 

 an account. 



I. On the Existence of a Pharynx and of Teeth in the Poly gastric 

 Infusoria, 



In his earlier works, M. Ehrenberg had fixed on the want of 

 a pharynx as a distinctive character of the class Polygastrica ; 

 whilst this organ, accompanied with teeth, was found conspicu- 

 ously to exist in the class Rotatoria ; but, by certain improve- 

 ments in his microscopes, he has more recently succeeded in dis- 

 tinctly discovering teeth in the Loocodes ci/cuUuIus (Kolpoda cu- 

 cuUulus, Miiller). This discovery he published in his second 

 memoir on microscopic beings ; and his attention being thus 



• Organisation in der Richtung des Kleinsten Raumes. Driiter Beitrag. 

 Von C. G. Ehrenberg. Folio, 11 Plates. Berlin 1834. 



