210 General Notes. 
species of Cyclops, say C. signatus (= C. coronatus Cls), we 
a form not at all rare but less abundant than C. fenuicor, 
which it seems to be constantly associated. In our investi 
we found Signatus almost constantly larger, 2” the same gathe 
than Tenuicornis. The only distinction, among those given 
either Claus or Brady, which is constant is the following; in 
natus the last joint of the antennz has a longitudinal ridge: 
like a pruning knife-blade extending beyond the end ini 
with the proximal two-thirds of its length strongly toothed. 
allied to C. parcus Her. found in Alabama, but this has no k 
like ridge.) The two species agree in having the ridge which 
tends nearly to the base of the antenna; they both have ce 
series of spines arranged upon definite parts of the antenna; boi 
have the circular series of spines on the basal joint of the fifth foi 
-in short there is a complete agreement even to the micro 
tails—aside from the teeth above mentioned. 
of but few joints ina similar condition. This fact alters 
is the last form, in exceptional cases of the common spí 
but a step further to show that as C. tenuicornis isa more! 
xamine, 
and somewhat altered forms. These large, or post-l 
appear to be dependent upon abundance of food and 
warm habitat. 
The species considered identical with Diaptomus castor 
