ASTACUS. 15%: 
in young specimens the posterior spines of the carapace are obsolescent and 
the hands of nearly equal size. Judging from his figure, 1 /, the postearapace 
is also longer. Perhaps these young specimens were A. Trowbridyii Stimpson. 
A. lemiusculus is closely related to A. Trowbridgii. For the distinctions, see 
under the latter species. 
The posterior margin of the anterior seement of the telson is bi- or tri- 
spinous on each side. The cone at the orifice of the green gland (“ auditory 
tubercle”) terminates in a sharp spinule ; in A. 7rowbridgii it is blunt. The 
spines on the second and third segments of the antennx are prominently 
developed and acute. The anterior process of the epistoma is triangular, 
similar in form to that of A. Trowbridgii. The fingers are spinulose at the 
distal ends, as in A. Trowbridgit. 
Astacus Oreganus. 
Astacus Oreganus, Ranvatt, Journ. Acad. Nat. Sci. Phila., VIII. 138, Pl. VIT., 1839. 
Astacus Oreganus, De Kay, Zodlogy of New York, Pt. VI., Crustacea, p. 23, 1844. (After Randall.) 
Astacus Oreganus, ERrcuson, Arch. Naturgesch., XII. Jahrg., 7. 875, 1846. (After Randall.) 
Cambarus Oreganus, Girard, Proc. Acad. Nat. Sci. Phila., VI. 87, 1852. (After Randall. No description.) 
Astacus Oreganus, Stimpson, Journ. Bost. Soc. Nat. Hist., VI. 495, 1857. (After Randall.) 
Astacus Oreganus, HaceEn, Ill. Cat. Mus. Comp. Zodl., No. IIT. p. 95,1870. (After Randall.) 
“Testa granulata, bimaculata, fronte valde producta. 
“Body fuscous, granulated, carpus with a sharp spine at the inner angle; arm pro- 
duced into a spine on each side anteriorly; thorax behind the front with five spines, 
placed three before and one on each side behind the lateral ones; a large reddish spot 
on each side posteriorly ; front little reflexed on the sides, terminating in a very long 
slender spine, and having a short marginal spine on each side. 
“Length about four inches. 
“Taken by Mr. Nuttall in the Columbia River, west coast of North America.” — 
Randall. 
The type of A. Oreganus was lost or destroyed while in the hands of the artist by 
whom the drawing was made,* and no specimen answering to the description and figure 
has since been found. The figure given by Randall is very faulty, as has been pointed 
out by Hagen. The tri-articulate structures interpreted by Hagen as badly drawn anten- 
nal scales are, I think, the three distal segments of the third maxillipeds, the antennal 
scale not being represented at all. Dr. Hagen thinks that the median spine at the base 
of the rostrum may be a carinated elevation simply, such as is seen in A. nigrescens (he 
might have added also A. Trowbridgii and A. leniuseulus). The drawing might well be 
thus explained, but it is hard to make Randall’s explicit mention of five spines accord 
with such an interpretation. I incline, nevertheless, to Dr. Hagen’s opinion, that this 
specimen was no other than A. deniusculus Dana. The short post-carapace and long ros- 
tral acumen agree better with that species than with A. Trowbridgit. 
* See Proc. Acad. Nat. Sci. Phila., V. 30. 
