170 M. F. Dujardin on the Digestive Organs of Infusoria. 



XX. — On the Digestive Organs of Infusoria. 

 By M. F. Dujardin*. 



The experiments of artificial coloration had led M. Ehren- 

 bergto recognise in 1830 the existence of deglutition in many 

 Infusoria; considering at that time as stomachs all the vesicles 

 in which the colouring matter had lodged, this observer en- 

 deavoured to find out the mode of connexion of these stomachs 

 with a mouth and anus. Deceived undoubtedly by some il- 

 lusion, he thought he perceived a central tube, straight or va- 

 riously curved, to which the stomachic vesicles were attached 

 by still narrower tubes, like the berries of a bunch of grapes. 

 He described and figured Enchelys pupa with a straight intes- 

 tine, Leucophra patula with the intestine curved three times, 

 and Vorticella citrina with the intestine forming almost a com- 

 plete circle, and returning to open for excretion at the side of 

 the mouth. In the Monads, on the contrary, he represented 

 the stomachs as attached around the mouth by long pedicles, 

 and not affixed to the intestine. Although in the text of his 

 memoir he took care to state that the vesicles filled with a 

 solid nutriment are spherical and appear to be isolated, be- 

 cause the intestine which unites them contracts and becomes 

 transparent, yet his drawings, supposed to be made after na- 

 ture, represent this intestine equally extended everywhere, 

 and even filled with colouring matter in Vorticella, so that one 

 was naturally led to think that these representations were ideal. 

 It did not escape him that a vesicle was capable of dilating 

 considerably so as to contain a very voluminous prey, and con- 

 sequently he admitted that the intestine must have dilated 

 equally in order to allow it to pass. He had not yet noticed 

 the difference between the vesicles or the globules of the 

 interior, but he then attached so much importance to the dis- 

 covery which he thought to have made of the intestine of In- 

 fusoria, that he made it the basis of his classification, calling 

 Polygastrica the true Infusoria in opposition to the Rotatoria 

 which are monogastric, and which united by him under the 

 same denomination furnished false analogies. He distinguished 



*" Extracted from V. Dujardin 's * Memoire sur 1 'Organisation dos Infii- 

 soires,' Annales dcs Sciences Naturcllcs, November 1838. 



