A.STACUS. I:;:; 



in young specimens the posterior spines of (he carapace are obsolescent :unl 

 the hands of nearly equal si/.c. .hulking from liis figure, I /,. the postcarapace 

 is also longer. Perhaps these young specimens were .1. Trn'ln -lili/ii Slimpsoii. 



A. kimisntlus is closely related to A. 7 /</,"'//',/,///. For the distinctions, sec 

 under the latter species. 



The posterior margin of the anterior segment of the tclson is lii- or tri- 

 spinous on each side. The cone at the orilice of the green gland (" auditory 

 tubercle") terminates in a sharp spinule ; in A. Tr<>n<l>ri<li/ii it is blunt. Tin- 

 spines on the second and third segments of the antenna; are prominently 

 developed and acnte. 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. Trowlridyii. 



Astacus Oreganus. 



Asians Oreganus, RANDALL, Journ. Acad. Nat. Sci. Phila., VIII. 138, PI. VII., 1830. 



Astacus Oreganus, DE KAY, Zoology of New York, Pt. VI., Crustacea, p. 23, 1S44. (After Randall.) 



.lx/iii-its Oregaitus, EiucHSON, Arch. Naturgesch., XII. Jahrg., I. 375, 1816. (After Randall.) 



Cauiharns Oregaiuts, GIRARD, Proc. Acad. Nat. Sci. Phila., VI. 87, 1S52. (After Randall. Xo description.) 



Asfdi-us Oregaaus, STIMPSON, Journ. Bost. Soc. Nat. Hist., VI. 495, 1857. (After Randall.) 



Astacus Oreyamts, HAGEN, 111. Cat. Mus. Comp. Zool., No. III. p. 95, 1S70. (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 reflexecl 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 Orcgnnus 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 lu-eii point-l 

 out by Hagen. The tri-articulate structures interpreted by Hagen as badly drawn anten- 

 na! scales are, I think, the three distal segments of the third maxillipcds, the anti-mml 

 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 

 illicit have added also A. Trowbridgii and A. leniv mlus). The drawing mijjl 

 thus explained, but it is hard to make Randall's explicit mention of fit 

 with such an interpretation. I incline, nevertheless, to Dr. Hagen's opinion, that 

 specimen was no other than A. /< niuseulus I >ana. The short post-carapace and long 

 tral acumen agree better with that species than with A. Troi>:l,rul,ju. 



* See Proc. Acad. Nat. Sci. 1'liila , V. 30. 



