DYSTERIA. 173 



between these jaws, there is not the least trace of an intestine, 

 nor of any definite cavity devoted to digestion. The food occu- 

 pies the whole length and breadth of the body under the same 

 circumstances as are observable in Paramecium, Pleuronerna, 

 Stentor, &c. 



The contractile vesicles are two (cv, cv l ) quite small globular 

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

 the other close to the base of the pivot; and although they con- 

 tract 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 colorless reproduc- 

 tive organ (ri) 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 

 (j) are not confined to this alone, for there are quite a number 

 of others which possess a similar apparatus at or near the mouth. 

 The Chilodon, which I have copied to illustrate Ehrenberg's idea 

 of the nature of the digestive system, has a complete circle of 

 straight rods (fig. 98, m) around the mouth. As for the pivot, 

 (fig. 100, pv,) 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 of Epistylis (fig. 95, p), Zoothamnium (fig. 104, jo), or 

 Podophrya (fig. 25) ; and as counter to what we see in these 

 last, I would state that there are certain of the Vorticellians, 

 closely related to Epistylis, which have no stem whatever, and 

 swim about as freely as Dysteria. 



What characterize them all, are not only the oblique relations 

 of right and left, but also the presence of one or more peculiar 



