THE CRUSTACEA OF NEW JERSEY. 6i 



deep hexagonal cells of various sizes. Eyes large, with few 

 facets, ocellus adjacent. Rostrumi long", acute, covered with 

 ridges and cells similar to those of valves. Labrum from side 

 view with anterior lobe blunt, posterior lobe digitates and ciliated 

 distally. Maxillae with two heavily ciliated teeth. Feet, five. 

 Post-abdomen broad, rounded distally, with twelve spines on 

 dorsal ot anal border. Claw strong, basal teeth two, proximal 

 smaller. Length about 0.55 mm. 



Male. — Unknown. (Doolittle.) 



Rauarks. — This species was originally found in lakes in 



Maine, and is recorded from P'rinceton, in 191 1, by its describer. 



In color it is said to be yellowish. The eggs are two. The Ngw 



Jersey examples are found to belong to the short-horned type. 



Family DAPIHNID^. 



Rami of antennae three and four-jointed. Five pairs of feet, 

 last with curved appendage guarding branchial sac. Antennules 

 oi female short, one-jointed. 



The members of this family are among the best known, and 

 some among the largest of the Cladocera. 



Key to the genera. 



a. Head beaked below : shell extending in sharp spine at upper posterior 



angle. daphne 



aa. Head somewhat beaked below; shell angled belo^v or extending in long 



spines from lower angle. scapholEbEris 



Genus DAPHNE Miiller. 



Daphne Miiller, Zool. Dan. Prodrom., 1776, p. 199. Type Monoculns pulex 



Linnaeus, second species. 

 Daphnia Miiller, Entomost Dan. Norweg., 1785, p. 79. Type Daphnia pen- 



nata Miiller, first species, designated as example by Latreille, Hist. Nat. 



Crust., HI, 1802, p. 17. 



Head beaked below. Shell extending in sharp spine at upper 

 posterior angle. Pigment fleck small. 



