216 
Eggs of this species are not carried by the parent for any length 
of time, so that reproductive cycles are not easily traced. The total 
number of the summer eggs of Syucheta will be found (Table I.) to 
fluctuate somewhat with the pulses of the species. The free winter 
eggs, belonging probably to both species of Syncheta, also show 
some tendency to predominate at and after the culmination (Table 
I.) of the pulses. A female carrying a male egg was recorded during 
the rise of the spring pulse in 1898, and attached winter eggs were 
noted at the vernal pulse in 1895 and 1897. The evidence points 
toward the culmination of these pulses in a sexual cycle. 
The soft and flexible nature of this rotifer and the absence of 
spinous outgrowths have made whatever variability the species 
possesses less evident than it isin such a genus as Brachtonus. ‘There 
is considerable variation in size—possibly due to age—even in the 
same collection. The determination of preserved material of this 
genus is fraught with insuperable difficulty. The separation of 
pectinata and stylata in our records is at the best only probable. It 
may be that other species of Syncheta have been included with the 
individuals referred to stylata. In any event the result of the 
division has led to symmetrical results comparable with those of 
other planktonts. Syncheta is often parasitized at the times of the 
larger pulses by some sporozoan (?). At the maximum of the 
vernal pulse in 1898 over 4 per cent. of the individuals were thus 
affected, the infestation continuing through the decline of the pulse. 
External parasites, Colacium and ‘Rhabdostyla, are rare. 
This species has not been found widely in the plankton, possibly 
because of the confusion of stylata, tremula, and pectinata in identifi- 
cation. From the large numbers reported in almost every instance 
where it has been found, the expectation of its wide-spread occur- 
rence is at least raised, waiving in this connection the possibility of 
specific confusion. Jennings (’94) found it to be very abundant in 
towings in Lake St. Clair, and (96) in Lake Michigan near Charle- 
voix. He finds it less abundant in the summer plankton of Lake 
Erie (’00). Stenroos (’98) reports it as one of the most abundant 
limnetic rotifers in Lake Nurmijarvi in Finland in the summer, and 
Skorikow (’97) finds that next to Polyarthra it is the most abundant 
rotifer in summer months in the River Udy near Charkow, Russia. 
His figures of occurrence show some traces of recurrent cycles in 
these months, with maximum numbers at the first of August. Lau- 
