i.. 



238 



GEOLOGICAT, AND NATURAL HISTORY 



XI. 



A NEW CYCLOPS 



By C. L. Herrick. 



Cyclops quadricornis lias often been used as an object for study 

 by those desirous of becoming familiar with the process of develop- 

 ment in Crustacea. For this it is eminently fitted both on account 

 of its very distinct changes and its abundance in every pond and 

 pool. 



Fig. 1. 



There is another member of the same genus which has not, 

 apparently, been described, and I have therefore provisionally 

 named it C. longicornis from the very long primary antennae. 



The appearance of an ordinary individual (Fig. 1.) is not very 

 widely different from the ordinary species. But the first glance 

 of the female with the spherical sac of ova under the abdomen 

 makes the creature seem quite distinct. 



The general appearance and its movements while swimming 

 briskly about cause it to look like a magnified cladocera, the long 



