218 Dr. C. F. J. Lachmann on the Organization of Infusoria, 



this canal into the interior of its body, apparently without any 

 swallowing movements on its part, so that it can hardly be 

 driven in, except by ciliary action. In others, on the contrary, 

 the cilia of the oesophagus appear to be wanting, as in Amphi- 

 leptus, Enchelys, Trachelius ; these perform regular movements 

 of deglutition, in order to overcome their prey, which usually 

 consists of Infusoria of tolerable size ; they push themselves, as 

 it were, with swallowing motions, like the Snakes, over their 

 prey, so that they can very rarely be fed with colour, and this 

 never forms stomach-like morsels, except when it is contained 

 in this form in the Infusoria devoured. The mouth in these 

 animals is sometimes placed at the anterior extremity [Coleps, 

 Enchelys), sometimes not {Trachelius, Amphileptus) ; the anus is 

 sometimes situated posteriorly, and sometimes not. 



This group of Infusoria is approached by those with peculiar 

 bacillar thickenings, or eel-pot-like teeth (Ehrenberg) in the 

 oesophagus, which is also collapsed. In these the oesophagus 

 usually extends in the form of a collapsed tube far beyond this 

 bacillar apparatus ; in Chilodon cucullulus, for example, nearly to 

 the posterior extremity of the animal. The mouth, which is 

 not unfrequently protrusible, is situated sometimes at the ante- 

 rior extremity of the animal {Prorodon), sometimes not {Chilodon, 

 Nassula, Liosiphon, Trachelius Ovum*). The anus is generally 

 placed at the posterior extremity of the animal, but in some 

 cases on the ventral surface near the hinder end {Chilodon cu- 

 cullulus, in which it is nearly on the right margin of the body). 



In the greater part of the Infusoria furnished with flagella, 

 the reception of food appears to take place in the same way as 

 in the last-mentioned groups of ciliated Infusoria. Although 

 Ehrenberg states that he saw the reception of food by Monadina 

 and Cryptomonadince, and figures coloured particles in animals 

 belonging to these families, this was denied by many, who 

 either thought that they were to be transferred to the vegetable 

 kingdom as unicellular plants, or regarded them as astomatous 

 animals. Cohnf was the first to re-establish the eating of these 

 animals, and I have also succeeded in seeing it in many of them; 

 I have not only seen coloured particles in the interior of the 

 body, of which, from the minuteness of the object, one might 

 always have remained in doubt as to whether they were really 

 contained in its interior, but I have also twice observed Mo- 

 7iadince which contained a small Bacillaria, the excretion of 

 which in the vicinity of the posterior extremity taking place soon 



* For the knowledge of the bacillar apparatus in the latter, I am indebted 

 to Dr. Lieberkiihn. 



t Entwickelungsgeschichte der niikrosko])ischen Algen und Pilze, p. 62 

 (Nova Acta Acad. C. L. vol. .\xiv. pt. i. p. 162). 



