Kolpodea.'] inpusorial animalcules. 585 



organs are visible. The curious star-like contractile vesicle in the 

 larger species is highly interesting, when physiologically considered, 

 as are also the little black bodies seen in P. aurelia. In four species 

 complete self-division, transverse and longitudinal, has been ob- 

 served alternately. 



Deriving its name from this genus, M. Dujardin establishes a 

 family ' Parameciens,'' partly correspondent vpith that of the 

 Kolpodea of Ehrenberg. This family comprehends "animals with a 

 soft, flexible body, of variable form, but mostly oblong, and more or 

 less depressed, provided with a loose reticulated integument, upon 

 which numerous vibratile cilia are distributed in regular series. 

 They also possess a mouth." 



"Lacrymaria, and Pleu7'onema, would probably be more correctly 

 placed in distinct families, the mouth in these being rather presumed 

 than demonstrated. The other genera properly referable to the 

 Parameciens are Glaucoma, Kolpoda, Paramecium, Amphileptus, 

 Loxophyllum, Chilodon, Panophrys, Nassula, Holophrya, and 

 Prorodon ; of these, all but the last two have the mouth lateral. 

 Chilodon, Nassida, and Prorodon, have teeth." 



Those genera, which are peculiar to Dujardin, will be found 

 appended at the end of the families of Ehrenberg, with which they 

 have the nearest relation. 



Paramecium aurelia (M.) — Body club-shaped cylindrical, slightly 

 attenuated anteriorly. An oblique longitudinal fold borders upon 

 the very receding mouth. Ehrenberg states that he has seen small 

 dark crystalline bodies abundant in the frontal region, which, he 

 conceives, are indications of the presence of nervous matter, as such 

 crystalline bodies often accompany it. These creatures appear to 

 have the sense of taste; and in the same group some individuals 

 prefer one kind of food, and others another. This interesting fact 

 may be observed by mixing blue and red colours together, when some 

 will feed upon the former, others upon the latter, as indicated by the 

 colour of the digestive cells: in some the cells have a violet hue. 

 These animalcules, fed with colour, may be dried upon glass or 

 mica, and thus preserved. The rays of the star-like vesicle 

 Ehrenberg considers as ductus spermatid ; they are long, and enter 

 the ovarium at many points. The expulsion of ova has frequently 



