Marsh—North American Species of Cyclops. 
1105 
widely separated. Schmeil says that the length nearly equals 
the last three segments. In our forms this is rarely the case, 
the length being more generally equal to the last two and a 
half of the third, or about three times the length of the last 
segment. In some cases the rami are shorter yet, as in some 
specimens collected in the Saskatchewan. The lateral seta is 
situated, at about two-thirds the length of the furca on the 
dorsal surface. A row of spines extends from the outer 
margin of the furca, on the dorsal surface opposite the -seta,, 
curving nearly to the center of the furca, and then nearly to 
the proximal end of the furca. Of the apical setae, the outer 
is spine like and short, the inner is slender and somewhat 
longer than the outer; the longest of the two middle ones nearly 
equals in length the cephalothorax. 
The first antennae (PI. LXXXI, fig. 2) of the female are 
composed of eight segments, are about two-thirds as long as the 
first cephalothoracic segment, and in repose lie nearly at right 
angles with the long axis of the animal. The fourth segment 
is the longest, and the fifth hears a sensory seta. The setae 
with which the antennal segments are armed, are, for the most 
part, long and stout. The segments near the base are quite 
stout, the first two being four times as wide as the terminal 
segment. 
The external margins of the segments of the swimming feet 
(PI. LXXXI, fig. 5) are armed with short, stout spines. The 
spinous armature of the terminal segments of the exopodites of 
the swimming feet is represented by the formula, 3, 4, 4, 3. 
The fifth foot (PI. LXXXI, fig. 4) consists of a single seg¬ 
ment, and is armed with one spine and two setae. 
The egg-sacs, pi. LXXXI, fig. 3, lie alongside the abdomen, 
and contain only a small number of eggs. 
The length of mature females varies from .7 mm. to .84 mm. 
This is somewhat smaller than the figures given by Schmeil 
for the European forms. 
Cyclops fimbriatus is not a common species, but is cosmopol¬ 
itan in its distribution. 
The synonomy is given before the description, and no ex- 
