132 BULLETIN 138, UNITED STATES NATIONAL MUSEUM 



Ambulatory legs (pi. 34, figs. 2 and 3) : Of the ambulatory legs 

 the carpus and the ischium are of about equal length and the merus 

 about twice as long as either. 



Measurements. — Eldorado specimens : Width of largest carapace, 

 measured on its circumference, G7 mm. ; width of largest palm 31 

 nmi. Approximate length of large specimen from tip of rostrum to 

 tip of telson 172 mm. ; length of abdomen 86 mm. 



Occurrence. — Oregon: Near Eldorado, Malheur County; Pliocene 

 series; ^*' upwards of 1,000 fragmentary specimens representing at 

 least 200 individuals in Yale Museum. 



Oregon: Section 34, township 19 south* range 43 east. Snake 

 River Valley, Malheur County; Payette formation, Miocene series; 

 three specimens representing at least two individuals; Cat. No. 

 353341, U.S.N.M. 



Oregon: Near Vale, Malheur County; Payette formation, Miocene 

 series; nine specimens; Cat. No. 353342, U.S.N.M. 



Idaho: Catharine's Creek (local name for upper part of Castle 

 Creek), Owyhee County; Pliocene series (?);^" J. C. Schenk, col- 

 lector, for Clarence King, in charge United States Geological Ex- 

 ploration of fortieth parallel; two abdomens, five carapaces, one 

 major and one minor manus ; Cat. No. 353343, U.S.N.M.^* 



"' Dr. John P. Buwalda writes, after a study of mammalian remains in Oregon : " I 

 think it probable that if the rock in which the crayfish were entombed is fairly well 

 indurated, the age can, with quite a high degree of probability, be assigned to upper 

 Miocene and lower Pliocene." 



^' Cope says of his species there is " great probability of their being later than Miocene, 

 and nothing to conflict with their determination as of Pliocene age." (Cope, Proc. Amer. 

 Philos. See, vol. 11, (1S70) 1871, p. 547; Faxon, Mem. Mus. Comp. Zool., vol. 10. 1885, 

 p. 156.) 



Vov discussion of the present state of knowledge in regard to the horizons of the 

 Castle Creek deposits, see Dall, Discovery of a Balkan fresh-water fauna in the Idaho 

 formation of Snake River Valley, Idaho. Professional Paper 132-G, U. S. Geological 

 Survey, 1924. 



^^ Although the two species above were said to be in the Smithsonian collection, they 

 were not sent there by Professor Cope. In 1881, Prof. A. S. Packard wrote (Bull. U., S. 

 Geol. Surv., vol. 6, no. 2, pp. 393 and 394) : " We may in this connection [description 

 of Cambartis piHmaevun] refer to tlie three fossil forms from Idaho Territory, described 

 by Prof. E. I). Cope, who has kindly allowed us to examine his type specimens (those of 

 4. subgrundialiH excepted), which were collected by Mr. Clarence King, in charge of the 

 survey of the fortieth parallel." In June, 1898, Prof. Packard wrote to Prof. George P. 

 Merrill : " I send tomorrow a small box containing the fossil Astacus from Idaho, which 

 was loaned by the late Professor Cope- and which was not returned to him. It should 

 be added to the National Museum." 



These specimens, 13 in number, are now in the National Museum. They were collected 

 by J. C. Schenk for Clarence King in Deposit 1, Catharine Creek, Pliocene series (?). 

 There are no specific labels attached to them, nor are they separated or separable into 

 two species. They do not appear to be the type specimensi described, but they may be 

 specimens from which the types were selected. If they really represent A. chenodeiina 

 and A. 1yrevifo7x;e-ps, then those species are synonymous. 



It is highly probable that Cope's A. subgruvdialis {loc. oit., p. 605) also is conspeciflc 

 with chenoderma for its chief character is the spination of the upper margin of the 

 chelae. Although I find no spines remaining on this margin, it is likely that many of 

 the coarse, broken tubercles present possessed in the beginning spiniform horny tips. 



