THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY, 



SUPPLEMENT TO VOL. XVIII. JANUARY 1847. 



XLVI. — On the Organization of the Poly gastric Infusoria. 

 By C. Eckhard*. 



[With two Plates.] 



1. Since the discovery and the progressive perfection of the 

 microscope, a new impulse has been given to all those branches of 

 scientific study in which its use is applicable, from which we can- 

 not withhold our acknowledgement, because it has enriched us 

 with a number of the most interesting facts, which formerly could 

 not have been anticipated. In botany, R. Brown, H. Mohl, M. J. 

 Schleiden and others have investigated with success ; and in the 

 zoological and anatomical department the not less important re- 

 searches of J. Muller, Bischoff, Schwann, Reichert, &c. have ap- 

 peared. Ehrenberg undoubtedly gave a most important impulse 

 to all these microscopic inquiries by his numerous investigations 

 in one class of animals, which before him had been examined 

 by few only, and the anatomical and physiological relations of 

 which at that time were almost unknown. Unfortunately how- 

 ever, this store of excellent observations has not been estimated 

 according to its true value; to many it has been inaccessible, 

 whilst others have either not repeated the observations, or only 

 imperfectly, and have hence expressed views which have not 

 stood the test of a critical examination. In the ( Lehrbuch der 

 vergleichenden Anatomie/ by Von Siebold and Starmius, which 

 appeared last year, in the section on the Infusoria, Siebold has 

 adopted views of their structure which totally differ from those of 

 Ehrenberg. Consequently these required thorough elucidation, 

 to separate mere opinions from what may be considered as well- 

 determined scientific facts ; especially since doubt has been thrown 

 upon even Ehrenberg's views, although founded upon distinct 

 observation. Schmidt has fully discussed Siebold' s views on the 

 structure of the Rotatoria in a previous part of this journal : 

 I shall attempt to do so as regards the Polygastrica in this paper. 

 My reasons for fully entering into the organization and physio- 

 logy of these animals, are, on the one hand, that we are at present 

 in possession of no treatise which lays before us the details of 

 this subject in connexion (for Ehrenberg' s observations are widely 



• Translated by Dr. J. W. Griffith from Wiegmann's Archiv, Part 3, 1 846. 

 Ann. 8f Mag. N. Hist. Vol. xviii. Suppl. 2 I 



