A NEW FRESH-WATER CRUSTACEAN. 
BY H. G ARM AN. 
Mancasellus macrourus, 11. sp. — Outline seen from 
above elongate oval, a trifle widest posteriorly. Terga 
convex, with an obtuse median ridge. Head excavated in 
front, with a slight niedian tooth, and a blunt prominence 
on each side midway between this and the lateral margin. 
A deep cleft in the expanded lateral portion of the head 
separates from the rest a posterior lobe on each side. 
Eyes opposite these clefts, rounded, prominent. Lateral 
edges of all the body segments behind the head rounded. 
Posterior segment very large and wide, a trifle hollowed 
out above the insertion of the caudal appendages. Most 
of the segments roughened on each side of the median ridge, 
all broadly explanate at the sides. Upper antennae small, 
about as long as the first four articles of the second pair; 
composed of nine segments, the first large, globose, short ; 
the second cylindrical, about as long as the three follow- 
ing together; third about twice as long as the fourth, re- 
mainder subequal. Second antennre reaching the posterior 
margin of the fifth body segment when drawn back ; pedi- 
cel composed of five segments, of which the first three are 
short, and the remaining two, long and cylindrical ; flagel- 
luin swollen at base. Mandibles without pal})i. First 
pair of legs of male with hand greatly swollen, oval, shin- 
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