194 Marsh — Cyclopidw and Calanidw of Wisconsin. 



The foregoing table will give an idea of the distribution of 

 the species in some of the bodies of water which I have exam- 

 ined. Green Lake is about seven miles long and has a max- 

 imum depth of a little less than two hundred feet. The other 

 lakes — the Great Lakes excepted — are shallow. Lake Winne- 

 bago, although a large body of water, is said to be nowhere 

 more than twenty-five or thirty feet in depth. Rush Lake is 

 pretty largely covered with a growth of rushes and wild rice, 

 and is being gradually filled up. Lake Puckaway is an expan- 

 sion of Fox river, is to a considerable extent covered with wild 

 rice and rushes, and is very shallow. 



FAMILY CALANIDW. 

 Genus DIAPTOMUS Westwood. 



KEY TO SPECIES OP DIAPTOMUS FROM CHARACTERISTICS OF MALE. 



Antepenultimate joint of antenna without appendage, 



Fifth feet nearly equal in length, oregonensis. 



Left fifth foot shorter than right, pallidus. 



Antepenultimate joint of antenna with hyaline lamella, leptopus. 

 Antepenultimate joint of antenna with appendage, 



Appendage short and blunt, sanguineus. 



Appendage as long or longer than penultimate joint, 



Terminal hook of right fifth foot broad, lateral spine 

 minute, minutus. 



Terminal hook falciform. 



Lateral spine nearer outer extremity of 



joint, sicilis. 



Lateral spine stout, near base of joint, ashlandi. 



