22 Infusoria from Fresh Water. [ January, 
shown in Fig. 6 under the name of V. utriculus, which resembles 
in form V. striata Duj., a salt-water infusorian. In its conspicu- 
ous surface striations it also suggests the marine animal, and in 
size, furthermore, the two somewhat closely correspond. In the 
comparative proportion of breadth and length they differ, also in 
width of peristome as well as in the length of their respective 
pedicels, that of the marine form being twice and that of the 
sweet-water species three times as long as the body. V. utriculus 
may be a fresh-water variety of V. striata. The coincidences of — 
{ 
Fig. 6, Fig. 7. 
Fic. 6.—Vorticella utriculus, sp. nov. X 437. Fic. 7.—Vorticella macrophya, sp. 
nov. X 535- 
form and other essential characters are at least interesting and 
suggestive. 
In its habitat it is disposed to be solitary, although it does not 
object to neighbors if not too near. Usually when one is found 
others are to be noted arranged singly on the same Lemna root- 
let, and at almost equal distances apart. When contracted the 
pedicel is coiled in close rings, and has its distal end sheathed by 
_ the posterior termination of the body in a manner similar to that 
of V. smaragdina when in the same inactive state. It is shown 
extended in Fig. 6, magnified 437 diameters, and may be de- 
scribed thus: 
