THE CRUSTACEA OF NEW JERSEY. 57 



dark pigment in its upper part. The males are very rare and 

 have been seen but seldom. 



Key to the sub-families. 



a. Digestive tract not coiled, with two caeca in front, and anus at end of 



post-abdomen. eurycercin^ 



aa. Digestive tract coiled, and anus near end of post-abdomen. lyncein.^ 



Sub-Family Eurycercin^. 



Intestine not coiled, with two caeca in front and vent at end 

 of post-abdomen. Many eggs produced at once. Male opening 

 at base of abdomen. Males appearing in autumn. 



Genus EURYCERCUS Baird. 



Eurycercus Baird, Ann. Mag. Nat. Hist., London, II, 1843. p. 88. Type 

 Lynceus lamellatus Miiller, monotypic. 



Characters contained in the sub-family. 



Eurycercus lamellatus (Miiller). 



Plate 6. 



Lynceus lamellatus Miiller, Zool. Dan. Prodrom., 1776, p. 199. Denmark. 

 Eurycercus lamellatus Turner, Geol. N. Hist. Surv. Minn., Zool. Ser., II, 1895, 

 p. 274. Kent County, Delaware. 



Description. — Shell large, mostly of very slight ovoid contour, 

 lower edge but little curved or scarcely so much as back, and ends 

 in a small point or spine behind. Posterior and lower edge of 

 shell sometimes with a series of fine hairs. Most of entire sur- 

 face of shell with fine or more or less obsolete transverse wavy 

 striae. Back depressed, with indention at root of neck. Head 

 rather triangular, large, rounded before and above eye. Eye 

 large, conspicuous, high. Beak rounded, obtuse. Antennules 

 rather short. Antennae moderate, filaments slightly plumose. 

 Fornices short, rounded, joined with beak by line suddenlv de- 



