308 CRAYFISHES. 
son anaranjados, color que se observa en la parte inferior del cuerpo e inferior e interna de las patas. 
Estas tltimas son de color bruno-olivaceo o bien oliviceo, especialmente en las quelas.’””# 
With reference to the large triangular colour-patch on each side of the 
carapace of P. bimaculatus as described by Philippi and of P. agassizii as de- 
scribed by Porter, it should be observed that spots of the same shape and in the 
same place are often seen in crayfishes of divers kinds shortly after they are im- 
mersed in alcohol. These spots or blotches are the result of the quick action of 
the alcohol on the thinnest part of the branchiostegites, which are bathed in the 
fluid on both sides, within and without. At first red, these spots afterwards 
fade into yellowish white,— the colour which ultimately pervades the whole 
of the body in specimens preserved in spirits. One is almost inclined to suspect 
that the colour-pattern noted by Philippi and Porter was due to recent immersion 
of the specimens in alcohol. 
ASTACUS LENIUSCULUS Dana. 
A large number of specimens of this species were collected for the U. S. 
National Museum in Johnson Creek, Portland, Multnomah Co., Oregon, by 
Messrs. Lyon and Benedict in May, 1905. The largest of these are upwards of 
five and one half inches long and demonstrate the fact that this species has as 
full, obese a form as A. trowbridgii. There is considerable variation in relative 
width of the areola in these specimens. Of twenty-six specimens, eighteen 
(7,11 9) have the right and left claws symmetrical, while in eight (5 7, 3 2) 
the claws are asymmetrical. In many of the asymmetrical individuals I think 
the smaller, slenderer claw, which may be either on the right or left side, is a 
new claw grown after the loss of the original one. 
In a male specimen collected by Mr. 8. E. Meek, in Ten-Mile Lake, Florence, 
Lane Co., Oregon, Oct. 17, 1896 (U.S. N: M. No. 23,121), the chelae have the 
form characteristic of A. leniwsculus, and both pairs of post-orbital spines are 
developed as in that species, but in the shape of the rostrum and the propor- 
tions of the areola it agrees with A. trowbridgii. Another specimen in the U. 8. 
National Museum from Astoria, Clatsop Co., Oregon, resembles A. trowbridgii in 
the breadth and inflation of the claws and the length of the posterior section of 
the carapace. Still another specimen in the same Museum (collected by Mr. 
Wm. Palmer) from the base of Mt. Tamalpais, Marin Co., Cal., taken altogether 
would be classed with A. trowbridgii; yet in the proportions of the posterior sec- 
1 Porter, op. cit., p. 258. 
