Jan., 1905.] 
Actinolophus minutus. 
261 
ACTINOLOPHUS MINUTUS A NEW HELIOZOAN, WITH A 
REVIEW OF THE SPECIES ENUMERATED IN 
THE GENUS.* 
L. B. Walton. 
While examining late in October some sediment in a jar con- 
taining Hydra jusca collected September 17, 1904, in the Koko- 
sing River, attention was attracted by a small stalked form of 
heliozoan like appearance. This (Fig. 1), a single example of 
which was observed, on more careful 
study proved referable to the genus 
Actinolophus (Heliozoa) the representa- 
tives of which are not met with fre- 
quently, none to the knowledge of_the 
present writer having thus far been noted 
in America. 
Although there is considerable uncer- 
tainty as to the exact relation of the spe- 
cies constituting the group to the other 
Protozoa, the characteristics of the form 
in question appear to merit record, dif- 
fering as it does from A. capitaUis Penard 
through the absence of knobbed pseu- 
dopodia as well as in its much smaller 
size, and from A. pedatus (Zach.) by the 
spherical form of the body which is ovoid 
in the latter and much larger than the 
body of A. minutus. 
Schulze, 1874, formed the genus 
Actinolophus for the reception of A . 
pedunculatus a marine form from the 
Baltic Sea described by him. Penard 
1890, described A. capitatus from a single 
individual suggesting its close relation- 
ship with the tentacliferous infusoria 
(Suctoria). Zacharias, 1893, in a brief 
description, called attention to a new 
Heliozoan, Actinosphceridium pedatus 
which Schaudinn, 1896, in his monograph 
of the Heliozoa, placed provisionally in 
the genus Actinolophus, recognizing for 
that genus three species, two of which were of doubtful value. Pen- 
ard, 1904, in his valuable monograph of the fresh water Heliozoa, 
mentions both A. capitatus and A. pedatus among forms whose 
position is doubtful, suggesting possible affinities with Tokophrya 
and Nuclearia, noting at the same time the desirability for further 
* Read before the Ohio State Academy of Science Nov. 26, 1904. 
Fig. 1. Actinolophus minutus 
n. sp. (x 1000), psd. — pseudopo- 
dia, c. V. — contractile vesicle ( ?), 
p. — pedicle, g. e. — gelatinous 
envelope, n. — nucleus. 
