FOSSIL ASTACID.E. 155 



No remains of Crustacea near the Astacidse have been found in the Wealden, which 

 is of fresh-water origin, while the Cretaceous has yielded the genera Hoploparia and 

 Enoploclytia, which closely resemble the recent Homaridas. Hoploparia is found also in 

 the London Clay (Eocene). 



Schluter* has described, under the name Astacus politics, a Decapod from the Lower 

 Chalk of Westphalia, in which the telson is divided by a transverse suture, as in the 

 majority of the Potainobiinae ; but the single specimen obtained is too imperfect to admit 

 of being definitely placed, the fore part of the carapace, including the rostrum, as well as 

 the terminal portion of all the legs, being lost.f 



It is only in the fresh-water Tertiary deposits of the Western United States that fossils 

 have been discovered which can be referred reasonably to the family Astacidse. Packard J 

 has described and figured by the name of Cambarus primcevus two specimens from tin' 

 Lower Tertiary beds (Eocene ?) of the Bear River Valley in Western Wyoming. Judging 

 from Packard's figures, I should think that these specimens belouged to Astacus rather 

 than to Cambarus. The shape of the antennal scale and the chelae indicate this. I fail 

 to see the close resemblance pointed out by Packard between these specimens and Cam- 

 barus affinis. The rostrum, as shown in the figures, resembles that of A. Dauricus as 

 nearly as any living form. With reference to the conditions under which these crayfishes 

 lived, Dr. Packard says : "The soft, fine, fissile, clayey shales of the Bear River Tertiaries 

 contain not only a good many herring-like fish, but also genuine skates. The presence 

 of land plants mingled with marine animals shows that the waters were fresh, but com- 

 municated with the sea; the conditions were apparently those of a deep estuary, into 

 which fresh-water streams ran, and in these rivers lived the crayfish. The deposits were 

 probably Eocene, if these divisions are to be retained for the Tertiary deposits of the 

 West, and may have been laid clown nearer the ocean than those of Green River." 



In 1870 Cope § described three extinct species of Astacus from fresh-water Tertiary- 

 deposits in the Territory of Idaho. The specimens were obtained by Clarence King, on 

 the expedition sent out for the geological exploration of the fortieth parallel west of the 

 Mississippi River. I have not been able to find the specimens in the Smithsonian Insti- 

 tution, where they belong. 



The first species described by Cope is named Astacus subgrundialis. Iu this form 

 the rostrum is narrow, concave above, acute, with five spinous points on each side and 

 a terminal recurved spinelet; two post-orbital tubercles on each side, the anterior pair 

 spiniform ; surface of the carapace smooth or obsoletely wrinkled ; abdominal pleura promi- 

 nent and acuminate, those of the second segment four times as wide as the others; chelae 

 nearly smooth, not granulate, the superior edge spiniferous; the longitudinal groove of the 

 carpus is well marked, and this segment, is not spiniferous; the antennal scales are large, 

 and extend nearly to the tip of the rostrum; areola of moderate width. Length to cervical 



* Ncue Pische and Krebse aus der Kreide von Westphalcn. Vou Dr. W. von dcr Marck und Dr. CI. 

 Schluter. Palaeontographica, XV. 302, Taf. XldV. figs. I. 5, L868, 



f So also with the genus Astacodes founded In Bell (Moil Foss. Mai I rust. Greal Britain, Pt. 



[I. Crust, of the Gaull and Gre< n aw*, p 30, PI. IX. figs. 1-0, 18G2j for the reception of K 

 Phillips from the Speeton Clay. 



{ "Fossil Crawfish from tlio Tertiaries of \\\ ing," bner. Nat., XIV. 222, 223, March, L880. "On 



;. Crayfish from the I. iwer Tertiary Beds of Western Wyoming," Bull. C S. Geolog. ami Geograph. Sun. 

 'fen-. \ I 391-397, with two cuts, September, L881. 



§ "On Time Extinct Astaci from the Fresh-water Tertiary of Idaho," Proc. Amer. Philosoph. Soc. 

 XI. 605-607, 1870. 



