as Infusoria flagellata. 259 



^' The most striking peculiarity of this creature is its habit 

 of swinging around on a pivot {Ji^) , which consists of an ovate 

 or lancet-shaped appendage, of considerable dimensions, that 

 projects from near the posterior end of the body, and in the 

 line of the row of cilia. The pivot possesses perfect flexibility 

 at its base, so that the animal can move over a considerable 

 distance backward and forward without distm-bing the point. 

 Most of the time it keeps the flat side down when gyrating 

 around its place of attachment ; but now and then it turns 

 upon its right edge, and performs its eccentric rotations about 

 the appendage. This is the habit which, as I said before, has 

 impressed some observers with its similarity to the Rotifera. 

 In connexion with this, too, it happens that the creature pos- 

 sesses a pair of jaw-like or, rather, pincer-like bodies (m^), 

 which lie near the entrance to the mouth, and occasionally 

 open and shut like a pair of forceps, just as similar bodies 

 known as the jaws of Rotifers do, whilst food is passing be- 

 tween them. Excepting the passage between these jaws, there 

 is not the least trace of an intestine, or of any definite cavity 

 devoted to digestion. The food occupies the whole length and 

 breadth of the body, under the same circumstances as are ob- 

 servable in Paramecium, Pleuronema, Stejito?-, &c. 



" The contractile vesicles are two {cv,cv) quite small globular 

 bodies, one of which is situated just to the right of the jaws 

 {m^)j and the other close to the base of the pivot (fl^) ; and, 

 although they contract very slowly (not oftener than once in 

 four or five minutes), they evince every characteristic, in action 

 and physiognomy, of true infusorian pulsating vesicles. The 

 large colourless reproductive organ [n] singularly exemplifies 

 in itself the one-sidedness of the animal, by its conformation to 

 the shape of the body. One side of it is convex, and, like the 

 rest of the organization, projects into the concavity of the 

 larger shell, whilst the other face is flat and, as it were, 

 moulded upon the plane shell. It forms a very conspicuous 

 object just to the left of the jaws, and might easily be mistaken 

 at first glance for a contractile vesicle, especially as the true 

 representatives of that organ are so very inconspicuous both in 

 regard to their size and actions. 



" Now in all the organization of this animal there is nothing 

 which is not strictly infusorian in character. The jaw-like 

 bodies (m^) are not confined to this alone; for there are quite a 

 number of others which possess a similar apparatus at or near 

 the mouth. Chilodon has a complete circle of straight rods 

 around the mouth. As for the pivot {fl^), it is nothing but a 

 kind of stem, such as exists on a larger scale in Stentor, or is 

 more peculiarly specialized in the pedestals oiEpistylis^Zooiham- 



