ENTOMOSTRACA OF MINNESOTA. 263 



rangiilar, smaller than the eye and half as far from it as from the 

 beak. The conical antennules bear two flagella, one near the end, the 

 other near the basal third. Shell longer than high, strongly arched 

 above, surface smooth. Anal teeth 13 or 14. Claws short and smooth 

 except for the two basal spines. (Matile says the claws are slightly 

 ciliate.) Length 0.54 to 0.59 mm. 



Chydorus pig-er Sars. 



Sub-rotund, prominent above, sinuate behind; lower and posterior 

 margins rounded, lower margin ciliated. Head movably united to 

 the body; beak long, separated by an indentation from the head 

 shield. The shell is broad, as seen from above. Shell punctate 

 anteriorly and marked below by indistinct oblique stride. Antennules 

 with seven setfe and two small thorns on the end of each ramus. 

 Post- abdomen truncate; the terminal claws with a minute tooth at 

 the base, posterior margin sinuated, rounded below and there densely 

 armed with minute teeth. Abdominal set£e long and flexible. Pig- 

 ment fleck of medium size, much nearer to the eye than to the beak. 

 Length about 0.33 mm. 



(?) Chydorus latifrous Dana. 

 (U. S. Exploring Expedition, Rep. on Crust., Vol. II, p. 1274.) 



Very tumid; inside view rotund, head not separate, very short- 

 beaked; beak slender and close to the body, acute; in upper view 

 animal very broad, truncate anteriorly, the front thereby nearly as 

 broad as the body; behind low, triangular and obtuse. Feejee 

 Islands. 



(?) Chydorus albicans Gay. 



From Chili. Is imperfectly described; but it is interesting to note 

 the occurrence of this genus there. 



Chydorus puuctatus Hellich. 



Very small, tumid, truncate caudad. Head low, with rather short, 

 sharp beak. Macula round, as large as the eye, to which it is nearer 

 than the beak. Antennules tumid at the middle, with lateral seta 

 above the middle. The ventral margin of the shell is very convex, 

 with long pectinate setse. Hexagonal reticulations, each with a cen- 

 tral elevation (°?) mark the shell. Post abdomen short, broad. Anal 

 teeth eight or nine, of uniform size. Claw with one basal spine and 

 a row of setai. Length 0.44 to 0.47 mm. The abdomen of the male is 

 curved and deeply excavated apically. Claws short and smooth. 

 Length 0.42 mm. This is probably only a variety of (7. sphcericus. 



