ENTOMOSTRACA OF MINNESOTA. 65 
iated process. Wedo not find in this species that the claw of the 
penultimate segment of the outer ramus is denticulate, though in some 
stages or forms it may be. The apical segment is obsolescent and bears 
two unequal spines. De Guerne and Richard figure an accessory spine 
at the base of the apical segment. There is occasionally a slight ten- 
dency for the inner ramus to appear obscurely two-jointed. The male 
feet of the fifth pair are very long. The inner rami are both rather 
long (longer than the segment of the outer ramus opposite which they 
stand), one-jointed, and slightly ciliated apically. The terminal claw 
of the right foot is short and slightly curved and denticulate toward 
the apex interiorly. The preceding segment has a short accessory 
spine. The segment bearing the two rami has a short spine laterally 
and is bristly exteriorly. The terminal segment of the outer ramus 
bears two spines and a few cilia, while the penultimate segment has a 
ciliated process inwardly near its apex. The armature of the third 
and fourth feet is similar, the apical segment of the outer ramus bear- 
ing an external short spine, one long spine and two sete at the tip, 
and three sete internally. Length of female 1.5 to 1.7 mm.; of male 
1.4 mm. 
Diaptomus tatricus Wierzejski. 
PLATE X, Fie. 8. 
Wierzejski ’82 (lacinulatus), and ’83; De Guerne and Richard ’89. 
A large, stout form, with antenne scarcely exceeding the thorax 
nd the last segment of the latter produced into a large spindle-shaped, 
protuberance. The antepenult joint of the male antenna with a hya- 
line lamina. Inner ramus of fifth feet of the female short, obscurely 
two-jointed; those of the male curved. A tooth is found on the mid- 
dle of the inner aspect of the basal segment of the left foot, and the 
apical segment of the outer ramus is forcipate. Length 2.1 mm. 
Color carmine red. 
Diaptomus coeruleus Fischer. 
PLATE IX, Fic. 7. ‘& 
S. Fischer ’53 (Cyclopsina ccerulea); Lubbock ’63; Poggenpol ’74; Uljanin ’74; 
De Guerne and Richard ’89. 
This widely distributed specics has been very frequently con- 
founded with D. castor, than which it is rather smaller and from which 
if differs in possessing a lamina on the antepenultimate segment of the 
male antenna. The antenne reach the candal stylets. The apical 
Segment of the outer ramus of the fifth foot of the female is well de- 
veloped and its inner spine is almost as long as the claw ofthe penulti- 
mate joint. The inner ramus is two-jointed and longer than the basal 
joint of the outer ramus. The inner rami of the male feet are one- 
jointed. Length1.8 mm. 
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