ENTOMOSTRACA OF MINNESOTA. 263 
rapgular, 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 piger 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 striz. Antennules 
with seven setz 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 sete long and flexible. Pig- 
ment fleck of medium size, much nearer to the eye than to the beak. 
Length about 0.33 mm. 
(2?) Chydorus latifrons 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 punctatus 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 sete. 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 sete. 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 C. sphericus. 
