M. F. Dujardin on the Digestive Organs of Infusoria. 171 



the Anentera, which, unfurnished with intestines like the 

 Monads, have their pedicellated stomachs simply suspended 

 around the mouth, and the Enterodela which possess an in- 

 testine. 



These were divided into Cycloccela, Orthocoela, and Campy- 

 locoela, according to whether the intestine formed a circle as in 

 the Vorticel/a, straight as in Enchelys, or contorted as in the 

 Leucophra ; but the author, to conform, he observes, to the 

 received laws of zoology, immediately substituted for these di- 

 visions other sections established on external characters de- 

 pending on the position of the intestine, i. e. on the position 

 of the anus and mouth. He thus termed Anopisthia the Cy- 

 clocoela which have the two apertures united in front; Enan- 

 tiotreta those with the two apertures opposite and situated at 

 the extremities of the body, and which may be subdivided into 

 Orthocoela and Campyloccela ; Allotreta those having one of the 

 apertures terminal, the other lateral; and lastly Katotreta, those 

 in which both apertures are lateral or non-terminal. In his 

 second memoir (1832), M. Ehrenberg, without adducing new 

 facts in support of his opinion, developed further his first ideas. 

 In his third memoir (1833) he figured in two new types Chi- 

 loclon cucullus and Stylonychia mitylus, the intestine as large, if 

 not larger than in the three preceding species, which seems to 

 be in contradiction to the extreme contractability which would 

 have concealed this organ from the persevering investigations 

 of other observers. At the same time he began to establish 

 a distinction between the vesicles which can be filled by the 

 colouring matter, and those which, always containing a dia- 

 phanous fluid and generally more voluminous and less suscep- 

 tible of sudden contractions, are considered by him to be the 

 male organs of generation. Even in 1 776 Spallanzani had men- 

 tioned in the Paramcecice these latter vesicles, which in this 

 species are stelliform, but had assigned respiratory functions 

 to them. M. Ehrenberg, on the contrary, following up his 

 ideas of the signification or analogies of these parts, has af- 

 forded himself a means of solving, in appearance, the difficul- 

 ties presented by the explanation of the functions of all these 

 inner vesicles. 



In his large work recently published in 1838, he has re- 



