Diaptomns, 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 pallidum — that of the left 

 fifth foot of the male — and it is mainly from this figure that I 

 have considered D. pallidum 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. pallidas in only one locality — Heart Lake. 

 a small shallow lake south of Marquette. 



Diaptomus sicilis Forbes. 

 Plate III. 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. " " DeGuerne and Richard (30) p. 23, figs. 13 and 



14, pi. II, fig 13. 

 1891. D. sicilis Forbes (35) p. 702, pi. 1, fig 6. 



