198 Marsh—Cyclopiclce and Calanidce of Wisconsin. 
This species, which is abundant in the Great Lakes, I found 
as a common pelagic species in Green Lake in the summers of 
1890 and 1891. In a large number of collections made in 1892, 
however, I did not find a single individual. This seems par¬ 
ticularly strange, as the collections in 1892 were made at 
about the same seasons as in the preceding years. 
The Green Lake specimens differ slightly from Forbes’s type. 
They are somewhat smaller, the males averaging .9 mm., and 
the females 1.08 mm. The inner rami of the male fifth feet are 
not evidently two-jointed. 
Diaptomus ashlandi sp. nov. 
Plate III. Figs. 11-13. 
A small pelagic species closely resembling D. sicilis Forbes. 
In form it is slender, hardly to be distinguished from D. sicilis 
and D. minutus. 
The first joint of the abdomen in the female is longer than 
the remaining part of the abdomen, is dilated at the sides, and 
bears two minute lateral spines. The second and third joints 
are so closely united that the abdomen appears two-jointed. 
The furcal joints are about twice as long as broad. 
The antennae reach just beyond the furca. The right antenna 
of the male is much swollen anterior to the geniculating joint, 
and bears on the antepenultimate joint an appendage slightly 
exceeding in length the penultimate joint. This appendage 
may be blunt pointed or slightly enlarged at the extremity. 
The fifth feet of the female are rather slender; the outer 
ramus is two-jointed. The third joint is represented by two 
short spines. The inner ramus is one-jointed, a little longer 
than the first joint of the outer ramus, armed at tip with two 
rather long spines. 
The fifth feet of the male are slender. The basal joint of 
the right foot is about twice as long as that of the left. The 
first joint of the outer ramus is a little wider than long. The 
second joint is wider at the inner than at the outer end; the 
