Dr. C. F. J. Lachmaiin on the Organization of Infusoria. 215 



XIX. — On the Organization of the Infusoria, especiullij the Vor- 

 ticelUc. By Dr. C. F. J. L.vciimanx. 



[Concluded from page 128.] 



In the Infusoria we have found the alimentary apparatus to be 

 a large nutritive or stomachal cavity filled with chyme^ and fur- 

 nished with a mouth and anus. In the Vorfice//ina we have 

 seen an CEsophagus, ciliated internally, depending from the 

 mouth, and widening below into the pharynx. The internally 

 ciliated oesophagus occurs also in many other Infusoria, but its 

 dilatation into a pharynx is to be detected in no other family. 



The oesophagus [Schlund), beset internally with fine cilia, and 

 terminating below by an oblique truncation without dilating 

 into a pharynx, is most distinctly seen in the Paramecia and the 

 allied genera. In these animals, which are furnished with uni- 

 form fine cilia, sometimes all over and sometimes only upon a 

 considerable portion of the body, and in which there is no row 

 of stronger cilia leading to the mouth, after a morsel has been 

 passed from the oesophagus into the alimentary cavity, we see 

 the latter distinctly with a somewhat oblique termination; a 

 little drop of water is then soon whirled through its lower ex- 

 tremity, against the tenacious fluid chyme-mass by which it is 

 limited; the drop gradually becomes larger, and is completely 

 surrounded by the chyme, the lower extremity of the oesophagus 

 being applied to it only on one side. When the morsel thus 

 formed has attained a certain size, which is not always the same, 

 it is passed into the chyme-mass, where it then behaves in the 

 same way as the fusiform masses of the Vorticellince, and also 

 soon participates in the rotation of the chyme. In these ani- 

 mals also, as in the Vorticellince and all Infusoria furnished with 

 a ciliated oesophagus, the water and food, instead of being united 

 into drops or morsels, may be mixed at once with the chyme, 

 evidently from an altered condition of the latter. In these In- 

 fusoria (Ehrenberg's Colpodea, with the exception of the species 

 oi Amphileptus and Uroleptus^, the Cijclidina of Ehrenberg and 



* With Focke I refer Loxodes Bursaria, Ehrbg., to Paramecium, as 

 the situation of the anus at the hinder extremity of the body does not 

 appear to me sufficient for a generic separation of this animal fi-om the 

 closely allied Paramecia, the anus in Paramecium Colpoda being placed 

 very near the hinder extremity, which is still more strikingly the case in a 

 new colourless Paramecium very nearly related to the colourless P. Bur- 

 saria. I do not, however, with Perty, think it necessarj" to revive O. F. 

 Miiller's name of Paramecium versufum, as there is scarcely ever any cer- 

 tainty in the synonymy previous to Ehrenberg; and I think therefore that 

 we should never again introduce an ohler specitic name for an Infusorium, 

 if it has a name given to it by Ehrenberg, even when it is not improbable 



