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ENTOMOSTRACA OF MINNESOTA. 175 
abundantly everywhere. In this country at least it is characterized 
by a dark color. The head is large, rounded in front of the large eye, 
serrate below and extending posteriorly into a roundish beak, back of 
which are the short antennules. The fornices are very short and 
rounded; a line connects the fornices with the beak by a sudden de- 
flection downward; it sets off the area which forms a part of the basin 
of the antenne. A second line springing from just above the termin- 
ation of the fornices passes over the eye by a broad curve. The post- 
abdomen is truncate and bears beside the terminal claws four or more 
spines which rapidly decrease in size. The claws are minutely spined; 
the spines on the shell are of variable length, but do not exceed one- 
fourth the length of the remainder of the lower margin. This species 
ranges over all Europe and eastern United States. 
Length 0.6 to 0.8 mm. 
Scapholeberis cornuta Schoedler. 
PLATE XLV, Fic. 6. 
Monoculus bispinosus—De Geer. 
Daphnia mucronata var. acute rostrata—Baird. 
Scapholeberis mucronata var. fronte cornuta—P. E. Mueller. 
This species differs from the above only in having a sharp curved 
horn on the head in front of the eye. The use of this appendage can 
only be conjectured; but it may be that, like the curved beak of Rip- 
ophilus, it serves to clear away rubbish in the filth in which these ani- 
mals frequently live. This form, be it variety or species, is not known 
in America. 
* Scapholeberis armata Herrick. 
PLATE XLII, Fies. 10, 11. 
Scapholeberis mucronata var. armata—Herrick. 
A very beautiful and unique species, which possesses the extreme 
development of the peculiarities of the genus, The head is shaped 
very much as in the previous species, the fornix is squarish, the basin 
for the antenne is small. The upper lines from the fornix meet be- 
hind the eye; the form of the shell is as in the above, but the spines 
upon the lower margin are longer. The scythe-likespine on the lower 
angles of the valves is extremely long, falling little short, in extreme 
cases, of being as long as the entire lower margin, in others about one- 
half as large. There are the usual lines parallel to the lower edge 
of the shell. The specimens having the longest spines were found in 
fresh water about Mobile, Ala., but the species occurs in Minnesota 
and intermediate points, though sparingly. Probably the earlier plan 
of regarding this as a variety of S. mucronata is nearer correct. 
