454 Wisconsin Academy of Sciences, Arts, and Letters. 
diaptomus lintoni Forbes. 
Plate XXVII, figs. 4, 5, 7. 
1893. Diaptomus Lintoni Forbes, p. 252; pi. XLII, figs. 26- 
28. 
1895. Diaptomus Lintoni Herrick and Turner, p. 68; pi. V, 
fig. 12. 
1897. Diaptomus Lintoni Schacht, p. 127; pi XXVII, fig. 1. 
“A large red species occurring commonly with D. shoshone; 
but distinguishable from it at a glance by its different shape, 
its longer antennae, its smaller size, and by characters derived 
from the right antenna and the fifth foot of the male. The 
thorax is symmetrically elliptical in shape, broadest at the 
middle. The posterior angles are not produced or bifid, but 
are each armed with a minute spine. The first segment of the 
abdomen of the female is not especially produced, but bears at 
its broadest part a minute spine on each side. The abdomen 
itself is very short, its length contained about three and one- 
third times in that of the cephalothorax. The antenna of the 
female is long and slender, 25-jointed, reaching a little beyond 
the tip of the abdomen. 
“The fifth pair of legs in this sex is similar to those of D. 
shoshone, but much smaller. The inner ramus is not jointed. 
It is longer than the basal joint of the outer ramus, bears two 
stout plumose setae at its tip, somewhat shorter than the ramus 
itself, and has likewise at its inner tip a patch of small sjnnes 
or fine hairs. The second segment of the outer ramus with 
its terminal claw is two-thirds as long again as the preceding 
segment, the breadth of the latter two-thirds its length. The 
third joint is indicated by a single long, stout seta and one or 
two smaller ones. 
“In the male the geniculate antenna is relatively rather slen¬ 
der, its last two joints without special appendages, its penulti¬ 
mate with a slender transparent apical process, reaching about 
to the middle of the succeeding segment, acute at tip, but 
neither serrate nor emarginate. 
