98 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 
tions particularly that it was found oftener at night than during the 
day. In America a similar species was described from near Paducah, 
Ky., under the name (C. tenuwissimus; but the possibility of identity 
with the Scandinavian species seemed excluded by the habitat. <A 
gathering taken at night from one of the lakes near Minneapolis con- 
tained a few specimens of similar characters, and there no longer 
seems to be a doubt of the identity or very close relation between 
these forms. 
‘“The antenne are longer than described for C. tenwissimus, nearly 
equalling the thorax. The last joint of the antenne is short, but the 
toothed character was not noted. The fifth feet are small, the spines 
are very long and slender. The margins of the abdominal segments 
are irregularly toothed. The species will be confused with no other. 
It is marked with blue in spots. Length 0.5 to 1.0 mm.”’ 
Cyclops scourfieldi Brady. 
Brady ’91. 
It is very difficult to determine whether we have in this species 
a variety of C. leuckarti or a distinct species. Brady identifies it with 
Sars’ C. leuckarti, which is regarded as distinct from Claus’ (. leuckarti. 
Schmeil has decided, after examination of Sars’ specimens, that they 
belong to (C. leuckarti Claus, and are the same as C. simplex of other 
authors. Under these circumstances there would seem to be no rea- 
son for hesitating in referring C. scourfieldi to C. leuckarti were it not 
that the figure of the fourth foot given by Brady differs in armature 
from that of Schmeil, and Brady fails to remark the striking armature 
of the last joint of the antenna. If Schmeil is correct in saying that 
the pearling or crenulation of the posterior margin of the mavxilliped 
is diagnostic of CO. leuckarti, the matter would be settled at once, for 
Brady clearly figures it. On the whole, we incline to believe that 
Brady’s figure incorrectly shows a seta where there should be a spine 
at the apex of the outer ramus of the fourth foot and that he has over- 
looked the hyaline plate on the antenna. He says, however, ‘‘the 
character which, so far as I know, distinguishes at once C. scourfieldi 
from all other species is the presence, on the second joint of the pos- 
terior maxilliped, of a series of short marginal spines.’’ Length 1.4 
mm. It may be added, that, in a figure of what is considered a va- 
riety of C. scourfieldi, the armature of the outer ramus is figured as it 
occurs in C. leuckarti, while that of the inner ramus is obviously inac- 
curate. 
*Cyclops oithonoides Sars. 
Very slender, thorax twice as long as wide, abdomen narrow, length 
compared to that of the thorax as 9:13. Stylets about twice as long as 
wide, strongly divergent, with short sete; the lateral seta near the 
