. Po aes, Pay te iA ~ 
ENTOMOSTRACA OF MINNESOTA. De 
The above is extracted verbatim from the Alabama Crustacea, which 
Professor Birge should have consulted before saying ‘‘none of the 
specific characters are mentioned or figured”’ (Birge ’91). 
Professor Birge is inclined to identify our species with I. longiremis 
Sars, from Australia. But if the Madison specimens have antennary 
sete nearly equaling the total length of the animal, they differ from 
all individuals of J. spinifer yet seen. The armature of the post-ab- 
domen is also different, for there are but four elongated claws at the 
inferior angle and a series of about 14 anal spines and six longer supra- 
anal teeth. We infer from Birge’s figure that the antenne are dif- 
ferent. It would be well that the Madison form should be more eare- 
fully described and figured and compared with other American species. 
Length 0.60 mm., height 0.46 mm., base of antenna 0.19 mm., four- 
jointed ramus 0.13 mm., post-abdomen 0.19 mm., claw 0.125 mm., long 
post anal spines 0.06 mm., antennule 0.10 mm. 
Ilyoeryptus acutifrons Sars. 
BGA Suivi) EG. a. 
This species is only mentioned in the appendix to the paper of Sars 
on the Cladocera from the vicinity of Christiania. The following is a 
condensation of the description. 
Head large, acute in front. Shell truncate behind, with shorter 
setee behind than below. Antennules shorter and thicker than in 
I. sordidus. Antenne long and robust. Abdomen with a short, obtuse 
process. Post-abdomen shorter than in J. sordidus, posterior margin 
continuous, anus terminal; caudal claws straight, very long, with two 
minute basal spines and a cluster of teeth in front. Pigment fleck 
almost touching the eye. Length less than in J. sordidus, 0.6 mm. 
In this species the moult is perfect. (See table above. ) 
*Tlyoeryptus longiremis Sars. 
PLATE LV, Fia. 5. 
Sars ’88; Birge ’91. 
Professor Birge finds this species abundant near Madison. The 
original description is not now accessible. It appears, however, that 
the form of the post-abdomen is very similar to J. spinifer, while its 
armature is quite different. The sets of the antenne are very long, 
nearly equaling the length of the body. ‘There are five to seven 
super-anal teeth, largest in the middle, an outer row of about eight 
long post-anal spines and an inner row of 11 to 12 post-anal denticles, 
besides several very small teeth near the terminal claw. There are 
three or four denticles on each side of the anus. The moult is incom- 
plete as in J. spinifer. 
