Diaptomus , 
197 
a regular curvature, and is about once and a half the length of 
the second joint. The inner ramus is slender, one-jointed, as 
long as the first joint of the outer ramus. 
The left foot extends to nearly one half the length of the 
second joint of the outer ramus of the right. The first joint of 
the outer ramus is about as long as the first joint of the outer 
ramus of the right foot. The second joint terminates in two 
projections,—a blunt finger-like process on the exterior side, 
with a pad armed with minute spines on its inner surface, and 
a slender falciform process from the inner margin, which curves 
over and nearly meets the process on the outer margin. There 
is also a small blunt projection on the inner margin of the 
joint. The inner ramus is slender, one-jointed, and. equals in 
length the first joint of the outer ramus. 
Length of the male, .875 mm. ; of the female, 1.01 mm. 
Locality, Heart Lake, near Marquette. 
Herrick’s descriptions of D. pallidas are not sufficient to 
identify the species, and his figures in the report of 1878 do 
not help the matter. In the final report on the Minnesota 
Crustacea, there is but one figure of pallidus —that of the left 
fifth foot of the male—and it is mainly from this figure that I 
have considered D . pallidus identical with my specimens. I 
have not found it quite as large as stated by Herrick, but in 
other respects it corresponds quite well with his descriptions, 
and it does not seem best to introduce a new name. 
I have found D. pallidus in only one locality—Heart Lake, 
a small shallow lake south of Marquette. 
Diaptomus sicilis Forbes. 
Plate ill. Figs. .8 and 10. 
1882. D. sicilis Forbes (22) p. 645, pi. VIII, figs. 9 and 20. 
1884. “ “ Herrick (26) p. 142, pi. Q, fig. 18. 
1889. “ “ DeG-uerne and Richard (30) p. 23, figs. 13 and 
14, pi. II, fig 13. 
1891. D. sicilis Forbes (35) p. 702, pi. 1, fig 6. 
