CAMBARUS. 97 
Cambarus virilis is subject to some variation in the shape of the rostrum, 
the punctation of the carapace, breadth of areola, etc., as Hagen pointed 
out in his account of this species, p. 64. Yet it is not liable to be con- 
founded with any other species if good-sized specimens are at hand. 
I have noticed in a few second-form (?) males of this species an inter- 
esting variation from the ordinary type of the first pair of abdominal ap- 
pendages. In most examples these appendages are split for a considerable 
distance from the tip, and the two rami are drawn out to a point at the tip. 
In the other specimens the whole appendage is stouter, the prominences 
more pronounced, the extremity is split to a less distance from the tip, and 
the ends of the rami are blunt, almost tubercutate. The hooks on the third 
pair of legs are well developed, as in the first-form male. The abdominal 
appendage is not articulated, but this is sometimes the case in the other and 
commoner type of abdominal appendage of the second-form males. I have 
found both these forms together in collections made at several places (Lake 
Superior, Lake Winnipeg, ete.), and the differences in the sexual appendages 
are not accompanied by any that would indicate a new species. 
A specimen of C. debilis from Baraboo River, Ironton, Wis., sent by Mr. 
Bundy, is the second form of the male of C. virils. 
Males are occasionally found with small hooks on the third segment of 
the second pair of legs, as well as on the third pair. 
From the U.S. National Museum I have received the types of Street’s 
C. Couesi and C. virilis. The differences between the two are very slight, 
and do not warrant their separation as two distinct species. Some of Hagen’s 
types of C. virilis from the Red River of the North and the Saskatchewan 
River are of precisely the same form as Street's C. Couesi. 
The following description of the living colors of C. vrilis is given by Dr. 
Streets from the notes of Dr. Coues on the specimens collected in the Souris 
River, Dakota : — 
“Carapace variegated with lighter and darker shades of brown: tail 
segment darker and more uniform brown, with large, symmetrical, dark 
brown spots, one on each side. Claws green, speckled with darker, with the 
protuberances yellow and reddish; other legs paler greenish. Below, in- 
cluding under side of the claws, greenish white, the claws speckled with dark 
spots. Antenne rich brown.” 
A large female specimen in the U. S. National Museum, collected by Mr. 
Edward Palmer in a pond near Bridgeport, Jackson Co., Ala., appears to 
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