28 C. BOVALLIUS. ASELLIDA. 
The first pair of antenne are as long as a fourth of the 
second pair, the flagellum is multi-articulate. 
The second pair of antenne& are shorter than the body, 
the flagellum multi-articulate. 
The mandibles want a palp. 
The lateral margins of the pereional segments are pro- 
duced. sligthly incised. 
The first pair of pereiopoda cheliform, with simple dac- 
tyli, the following pairs are equal, with pedunculated, bi- 
unguiculate dactyli. 
The uropoda are styliform, with narrow rami. 
1. Mancasellus tenax. " S. I. SMITH. 
Syn. 1871. Asellus tenax. S. I. SMITH (and A. E. VERRILL). >Notice of 
Invertebra dredged in La- 
ke Superior in 1871>, etc. 
The American Journal of 
Science and Arts. Third 
series. Vol. 2, p. 453. 
1874. Asellopsis tenar. > O. HARGER. >»On a new genus 
| of Asellide». The American 
Journal ofScience and Arts. 
Third series. Vol. 7, p. 601. 
1874. > > a (and O. HARGER) »The Crustacea 
of the fresh waters of the 
United States. Rep. of 
the U. S. Commissioner of” 
Fish and Fisheries. Part 
2, p. 659. 
1876. Mancasellus > > O. HARGER. »Description of Manc- 
asellus brachyurus, a new 
fresh water Isopod>. The 
American Journal of Sci- 
ence and Arts. Third series. 
Vol. 11, p. 304. 
The lateral margins of the head are deeply sinuated 
opposite the eyes. The eyes are small, prominent, they con- 
sist of many facets. The flagellum of the first pair of an- 
tenn&e is five-jointed. The second pair of antenne are half 
as long as the body. The pleon is large, only a little broader 
than long, sligtly rounded behind. The outer ramus of the 
uropoda is half as long as the inner; the inner one a little 
longer than the peduncle. 
