as Infusoria flagellata. 137 



base of the broad conical beak — a point at which, as will be 

 seen presently, the mouth is situated. 



The mouth (figs. 3, 4, m) lies between the base of the fla- 

 gellum {Jl) and the beak, or Iq) (//j»), as I shall hereafter de- 

 signate it, from its obvious office, presently to be described. 

 A plane, therefore, drawn through the lip and the base of the 

 flagellum, would also strike the mouth, and moreover form a 

 continuation of that of the greater diameter of the body. This 

 aperture is not visible during its closed state ; but its presence 

 has been often and unmistakeably determined by seeing the 

 masses of food enter invariably at the point designated above. 

 As already stated, particles are thrown with a sudden jerk, 

 precisely as is done \>j Anthoj)]tysa MuUeri, Bory (figs. 50, 51), 

 and apparently with great precision, directly against the mouth 

 (fig. 4, m). If acceptable for food, the flagellum presses its 

 base down upon the morsel, and at the same time the lip is 

 thrown back (fig. 4, l^?) so as to disclose the moutli, and then 

 bent over the particle as it sinks into the latter. When tlie 

 lip has obtained a fair hold upon the food, the flagellum with- 

 draws from its incumbent position and returns to its former 

 rigid, watchful condition (fig. 4, /?). The process of degluti- 

 tion is then carried on by the help of the lip alone, which ex- 

 pands laterally until it completely overlies the particle. All 

 this is done quite rapidly, in a few seconds ; and then the food 

 glides quickly into the depths of the body, and is enveloped in 

 a digestive vacuole {d)^ whilst the lip assumes its usual conical 

 shape and proportions. 



The contractile vesicle (figs. 2, 3, 4, cv) is a much larger and 

 far more active organ than that oi Ant]io2)hysa (figs. 47, 48, ci'). 

 If we view the body from its narrower aspect (fig. 2), when it 

 stands so that the lip (^j>) is nearest the eye, the contractile 

 vesicle {cv) appears in profile, on the left broad side, and so close 

 to the surface that it seems to project beyond the general outline 

 of the body. It lies in the anterior third of the broad side 

 jast mentioned, and close to the transverse plane which sepa- 

 rates that part which contains it from the one upon which the 

 lip is placed. From whichever direction, therefore, one views 

 this organ, it will be seen to stand in an asymmetrical relation 

 to the rest ; and as it is preeminently a dominant feature, it 

 may serve, perhaps better than any other, as a starting-point 

 in determining the obliquity of the type of this infusorian, 

 and its perfect consonance in this respect with that of the more 

 obviously spiral forms, such, for instance, as are exemplified 

 by Dysteria (figs. 77, 78) and Pleuronema (figs. 75, 76). It is 

 so large and conspicuous that its globu.lar form may be readily 

 seen, even through the greatest diameter of the body ; and it 



