ENTOMOSTRACA OF MINNESOTA. 107 
C. coronatus are ‘ allgemein bekannt,”’ though adding that Rehberg ad- 
mits that the young of the two species cannot be distinguished until 
the last moult, which seems to show that the late larve of C. coronatus 
are hardly ‘‘allgemein bekannt’’ even in Europe. Finally Schmeil 
denies the possibility of sexual precosity with the general statement 
that ‘‘Auch mir ist trotz der grossten Aufmerksamkeit unter den 
vielen Tausenden der von mir beobachteten Copepoden noch nicht ein 
einziges Mal eine solche Larve mit Hiballen zu Gesicht gekommen.”’ 
To this we can only say that such larve have been frequently seen 
during the last ten years, though only under certain conditions of time 
and place. Itis hoped to furnish conclusive evidence on this head 
svon if it is really needed. We had supposed that such precosity was 
now a well-recognized fact. It is to be hoped that careful embryolog- 
ical and biological studies may be instituted upon the Copepoda. 
Cyleops languidus Sars. 
PLATE XVII, Fias. 19, 11. 
Sars ’63; Herrick ’84; Schmeil ’91 and ’92; Richard ’91. 
This species has not yet been encountered in America, and from 
the extended discussion of Schmeil we still think there is considerable 
probability that this form is an illustration of retarded development 
of some 17-jointed species, perhaps ©. bicuspidatus. 
Cephalothorax attenuated anteriorly and posteriorly, narrow. 
. Abdomen slender. Stylets exceeding in length the two preceding 
segments. Lateral seta at two-thirds the length from the base, two 
median sete long, two lateral apical setz very short, the outer a ser- 
rate spine. 
Antenne slightly longer than the first segment, with short sete, 
16-jointed by the more or less complete fusion of the third and fourth 
segments. First feet with both rami two-jointed, formula: 
ex. 3 spines, ex. ‘1 seta. 
Outer ramus jap. 2 sete. Inner ramus ; ap. 1spine, 1 seta. 
in. 3 sete. in. 3 sete. 
Second foot with a three-jointed outer and two-jointed inner ramus. 
Formula as follows: 
ex. 2 spines. ex. 1 seta. 
Outer ramus { ap. 1 spine, 1 seta. Inner ramus + ap. 1 spine, 1 seta. 
in. 3 sete. in. 4 sete. 
Note.— The following measurements will serve to illustrate the usual proportions of variety 
tenuicornis: Total length, including stylets, 1.4 mm., first segment of thorax 0.5 mm., whole thorax 0.85 
mum., abdomen 0.52 mm., stylets 0.10 mm., antenne 0.85 mm., last joint of antennz 0.05 mm., longest 
caudal seta 0.55 mm., inner seta 0.30 mm. 
The corresponding measurements of C, curonatus are the following: Total length 1.66 mm,, first seg- 
ment 0.67 mm., entire thorax 1.12 mm., abdomen 0.54 mm., stylets 0.07 mm., longest seta 0.6 mm., inner 
seta 0.3 mm., antenne 0.95 mm. 
