1884.] Infusoria from Putrid Waters. 135 
_ ever, in connection with certain points of structure, compels its 
addition to the rapidly increasing list of new American species, 
while the possession of a pharynx from which spring rows of 
vibratile cilia, at once forces its admission into the above-men- 
tioned genus. 
The likeness of the hitherto single known species, 7i/lina mag- 
na Griiber, to Colpoda, has been remarked by its discoverer, but 
the resemblance between the latter and the form here referred to 
as Tillina saprophila, n. sp., is even more conspicuous than with 
the type, and would necessarily place it in the genus Colpoda were 
not the pharyngeal series of cilia present. These cilia are appa- 
rently larger but much shorter than those of the general cuticular 
surface, which are long and very fine. They are with difficulty 
separately resolved by the objective, unless the infusorium is in 
a weakened or dying condition; otherwise their motion is inces- 
sant, and they themselves become visible only through their effect. 
They depend from the entire internal surface of the membranous 
Pharynx, projecting slightly, if at all, beyond the oral aperture. 
The cilia of the general surface are extremely fine and, like those 
in the pharynx, can be satisfactorily distinguished only when the 
_ animal is quiescent, those situated anteriorly then showing them- 
= Selves to be somewhat the largest. The body is grooved oblique- 
ly, the striations being especially distinct on the anterior body half. 
The circular oral aperture is placed in the center of the ventral sur- 
_ ¥ace and, as the infusorium is swimming at ease, appears to be lat- 
eral. It is followed by the short membranous pharynx curving 
. toward the posterior extremity of the zodid and bearing the vibra- 
tile series already referred to. The endoplasm, usually colorless, 
encloses several linear straight or slightly curved dark-bordered 
ies, and numerous small corpuscles which at times render the 
y semi-opaque. The nucleus is large and situated near the 
‘enter of the dorsal region, commonly opposite, occasionally 
slightly in advance of the pharynx and oral aperture. The con- 
4 ctile vesicles increase in numbers with the creature’s age. In 
l ‘arly youth the pulsating vacuole is single and postero-terminal ; 
_ When the Tillina is mature, or nearly so, two, three or even four, 
eriorly placed, are not uncommon. When single, pulsations 
€ place about four times a minute. 
he Reproduction is accomplished by encystment followed by spore 
mation and by fission into two or more zodids, the young in 
