
159 
An examination of the location of the pulses of Asplanchna 
brightwellit shows (Table I.) that in 1898 one coincided with the 
pulse of chlorophyll-bearing organisms (Pl. II.) and the remaining 
four followed it either in a week or fortnight. In previous years 
two pulses coincide with and five follow those of chlorophyll-bearing 
organisms, and a single ill-defined one (Nov. 14, 1895) precedes. 
This species is not wholly herbivorous in its feeding habits. 
Codonella, Difflugia, and even other rotifers such as Brachionus and 
Anurea,are frequently seen in the digestive tract. Diatoms, even 
Melosira and Peridiniude, as well as Pediastrum and other alge, are 
frequently taken as food. Inone instance a Daphnia cucullata 300 
in length was seen in the stomach in a transverse position. It was 
fully a third the length of the animal which had eaten it. 
Asplanchna brightwella is reported by Skorikow (97) in the 
summer plankton of the Udy, in Russia; by Schorler (00) as spo- 
radic in the Elbe in June and September; and by Lauterborn (93) 
from the Rhine, where its cycle coincides with that of A. priodonta. 
Zacharias ('98) reports 1t in German reservoirs in June and August. 
It is a cosmopolitan species, but does not seem to have been found 
by other plankton investigators in European waters. 
Asplanchna ebbesborni Huds.—Average number of adults in 
1895, 942. In 1898, only winter eggs of the species were noted in 
the plankton in February, June, July, September, and October, 
though adults were doubtless there. Adults have doubtless oc- 
curred sporadically in all other years, and in 1895 reach a pulse of 
21,518 on July 6 at 81°, which was followed by the appearance of 
males and winter eggs. All records of adults lie between April 29 
and September 14 and above 60°. This rare rotifer has not appeared 
in the literature of fresh-water plankton elsewhere to my knowledge. 
Hempel’s statement (99) that his record of its occurrence in the 
Illinois is the first for this continent must be modified, since Leidy 
(87) found it near Philadelphia. It is evidently a summer plank- 
tont in our waters, and the wide distribution of its winter eggs 
suggests that it, too, may be polycyclic; and their appearance 
in the plankton in large numbers with reference to the adults taken, 
leads to the further inference that its center of distribution is prob- 
ably not in channel waters, and that it may be predominantly 
limicolous species, or have its center of distribution in the quieter 
backwaters. 
