540 The American Naturalist. [June, 
form. Later I had a chance to observe the two species side by side. In 
Stichotricha, likewise, the anterior part is much prolonged, the hair-like 
cilia are highly developed, and, as it seems, they serve not only for 
“tactile” purposes, but rather, at least in Stichospira, and very prob- 
ably also in Stichotricha, for guiding and directing the various parti- 
cles passing along with the current of water, partly to be arranged to 
the tube built by the animal itself, as Stichotricha has also the inclina- 
tion to, at least temporarily, live in cavities or self-made tubes. Sticho- 
spira must be regarded as a very much differentiated form of the same 
type, representing a different genus and even group. 
The animal was first noticed in March, 1894, when about a hundred 
specimens were seen, from a Small but healthy aquarium kept since 
early fall. Yet some points of the organization and life-history re- 
mained in doubt, and thus publication was deferred. Since May of 
that year, none were seen until recently, when again several dozen 
came under my observation, also in an aquarium, in company with 
many other ciliates, mostly living on, or rather in, small, old stems of 
Riccia. The observation and examination of this Infusorium presents 
its peculiar difficulties, as is apparent from the description. Thus, of 
conjugation and the forming of cysts, nothing has been seen; yet a 
publication seemed to be not out of place. 
EXPLANATION OF THE FIGURES. 
t tube. 
ev contractile vacuoles. 
-e  endoplasts, or “ nuclei” (fig. 3). 
p peristome. 
rpm right-peristome- a8 
` tpm left 
g gullet, lined with endoral cilia. 
fb food-ball in the gullet. 
-b food-balls in the posterior part of the body. 
db digested and waste food-ball passing to the 
a anus. 
um undulating membrane. 
ad adoral cilia. ¢ 
c single cilium at the anterior end. 
‘é additional smaller cilium. 
par paroral cilia (fig. 2) in a dense series. 
rm right marginal series of cilia. 
Im left “ 
-v ‘ventral’’ cilia. 
