THE WATER FLEAS (CLADOCERA) 739 



250 (249) Six pairs of feet, cylindrical, first pair very long; without branchial 



appendages Tribe II. Haplopoda. 



Sole family LEPTODORTDAE Lilljeborg. 



Head elongated, slender; eye filling anterior end. Body 4-jointed, the first part bearing 

 the 6 feet and dorsal brood-sac; the 3-jointed abdomen ends in 2 short stylets or claws. Anten- 

 nules small, freely movable. Antennae with very large basal joint; rami 4-jointed, with numer- 

 ous setae. Mandibles long, slender, pointed, with 3 spines near apex. Esophagus very long, 

 stomach in last abdominal segment. with very long antennules. The young from winter 

 eggs hatch as a nauplius. 



Sole genus with characters of family. .... Leptodora Lilljeborg. 



Sole species Leptodora kindtii (Focke) 1844. 



This beautiful, transparent creature is the largest of the Cladocera, the 9 reaching a length 

 of 1 8 mm. Rapacious, thbugh its weak mandibles prevent it from being formidable to the 

 harder shelled entomostraca; nocturnal in coming to the surface. 

 Limnetic in Great Lakes and small lakes in northern United States; not rare. 



FIG. 1170. Leptodora kindtii. 



IMPORTANT REFERENCES ON NORTH AMERICAN CLADOCERA. 



BIRGE, E. A. 1891. Notes on Cladocera II. List of Cladocera from Madi- 

 son, Wis. Trans. Wis. Acad., 8: 379-398; i pi. 



1893. Notes on Cladocera III. Descriptions of new and rare species. 

 Trans. Wis. Acad., 9: 275-317; i pi. 



1910. Notes on Cladocera IV. Descriptions of New and Rare Species 

 Chiefly Southern. Trans. Wis. Acad., 16: 1018-1066; 5 pi. 



HERRICK, C. L. 1895. Synopsis of the Entomostraca of Minnesota. Second 

 Report of State Zoologist; 337 pp., 81 pi. 



Contains much information and many figures, original and from various sources; but the 

 material is not very carefully or critically handled. 



