278 
IOWA ACADEMY OF SCIENCE Vor,. XXVII, 1920 
Lepadella ovalis (Muller) (Plate VI, Fig. 51). This was the most 
common species of the genus. It was found in great numbers in the 
canal (2), near West Okoboji (10), and in Green slough (12); less 
abundantly in the fish ponds (16), Sunken lake (17), and Eittle Spirit 
lake (19). 
Lepadella patella (Muller) (Plate VI, Fig. 52). A few individuals 
were found in the canal (2), the fish ponds (16), and Hottes lake (18). 
Lepadella triptera Ehrenberg (Plate VI, Fig. 53). This small Lepadella 
was found in water from a swamp near the head of Lake Okoboji (10), 
and in the fish ponds (16). 
Lophocharis oxysternon (Gosse) (Plate VI, Fig. 54). This species was 
found first in kettle hole (4) ; later two individuals were collected in a 
kettle hole near West Okoboji (10), and one in Little Spirit lake (19). 
Lophocharis salpina (Ehrenberg) (Plate VI„ Fig. 55). This Lopho- 
charis was found in a weedy marsh (14), in the fish ponds (16), and in 
Little Spirit lake (19) ; it is not abundant anywhere. 
Colurella adriatica Ehrenberg (Plate VI, Fig. 56). This species was 
found only near the mouth of drainage canal (2). Two specimens were 
found at different times. 
Colurella bicuspidata Ehrenberg (Plate VI, Fig. 57). This species, with 
C. obtusa, was found in a stagnant pool near West Okoboji (10). It 
seems to be very rare, as only one individual was found. 
Colurella deflexa (Ehrenberg) (Plate VI, Fig. 58). This Colurella was 
collected among weeds in the sand-bar pond (3) ; it was also found in 
a marsh near West Okoboji (10). Fairly common. 
Colurella obtusa (Gosse) (Plate VI, Fig. 59). This species was col- 
lected from a jar of Spirogyra which had been brought into the laboratory 
from the canal (2). It was later found in a stagnant pool near West 
Okoboji (10). Not common. 
Trichotria pocillum (Muller) (Plate VI, Fig. 60). This form was found 
on some algae brought from the canal (2). Three individuals were rec- 
ognized. . It was not found elsewhere. 
Trichotria tetractis (Ehrenberg) (Plate VI, Fig. 61). Found in a 
weedy marsh near Manhattan (14) ; two specimens. 
Macrochaetus collinsii (Gosse) (Plate VI, Fig. 62). This species was 
found in great abundance in the canal (2), but not until after the middle 
of August. 
Scandium longicaudum (Muller) (Plate VI, Fig. 63). Seven or eight 
specimens were found in water from the mouth of the canal (2). 
Trichocerca elongata (Gosse) (Plate VI, Fig. 64). Found in a tow 
from a sruall roadside pond near kettle hole (5) ; two specimens from 
the canal (2), and one from Little Spirit lake (19). 
Trichocerca lophoessa (Gosse) (Plate VI, Fig. 65). Only two indi- 
viduals of this species were found, both from a small pool near Center 
lake (13). 
Trichocerca rattus (Muller) (Plate VI, Fig. 66). This species is rather 
common. It was found first in a deep tow in Lake Okoboji (1) ; later, 
many specimens were found in the canal (2), in kettle hole (5), in 
Sunken lake (17), and in Hottes lake (18). 
