ASTACUS. 141 
A. One tubercle on each side of the base of rostrum. 
a. Tip of rostrum not exceeding the distal end of the penultimate segment of antennule. 
Rostrum not carinate at the tip. No spines on the sides of the carapace behind the 
cervical groove . . - . . . . A. torrentium. 
6. Tip of rostrum almost Ricans the ictal oud of the tecniinal segment of the antennule. 
A keel or median crest near the tip of the rostrum. One or more spines on the 
sides of the carapace behind the cervieal groove . . . : -.5 = 4 « Al pallines: 
B. Two tubercles, one behind the other, on each os of the base of ie rostrum. 
a. Margin of rostrum not “burials 
a. Margin of rostrum granulated, not continued back of the anterior post-orbital 
tubercle. Posterior post-orbital tubercle slightly developed . . . . . A. fluviatilis. 
8. Margin of rostrum smooth, continued back on the carapace as a distinct ridge as 
far as the posterior post-orbital tubercle. Posterior post-orbital tubercle well 
developed; provided withaspime . =. . . . =. . ..... =. + A. Colchicus. 
6. Margin of rostrum denticulate. 
a, Chela flat. Rostrum longer than peduncle of antennule. Basal angle of external 
border of antennal seale spinous . Oo < . . . . A. leptodactylus. 
B. Chela thick. Rostrum equal in length to medancle of meeniale Basal angle 
of external border of antennal scale not spinous sw ww... Ce A. patchy ps. 
6. Astacus torrentium. 
Cancer torrentium (Steinkrebs), Scorank, Fauna Boiea, ILI. 247, 1803. 
Astacus torrentium (Steinkrebs), Woxr, Mag. neuesten Zustand Naturkunde, herausgegeb. vy. Johann Hein- 
rich Voigt, XI. 42-45, Taf. I. figs. 1, 2, 1806. 
Astacus savatilis, Kocu, Deutschlands Crustaceen, Myriapoden und Arachniden, Heft 7, No. 1, with fig. 
(Panzer and Herrich-Schatfer’s Deutschlands Insecten, Heft 140, No. 1), 1835 ? 
Astacus tristis, Kocn, op. cit., Heft 7 (140), No. 2, with fig., 1835 ? 
Astacus torrentium, Kocu, op. cit., Helt 36 (186), No. 24, with fig., 1841. 
Astacus torrentium, Wricuson, Arch. Naturgesch., XI. Jahrg., I. 92, 1846. 
Astacus saxatilis, ERIcHSON, op. cit., p. 92, 1846. 
Astacus tristis, WRicuson, op. cit., p. 93, 1846. 
Steinkrebs, LEREBOULLET, Comptes Rendus Acad. Sci. Paris, XXXIIT. 379, 1851. 
Astacus longicornis, LEREBOULLET, Mém. Soe. Sci. Nat. Strasbourg, V. 2 (separate pagination), PI. I. figs. 
2-24, 1858. 
Astacus torrentium (Steinkrebs) (in part), Gerstretpt, Mém. Acad. Impér. Sci. St. Pétersbourg, IX. 574, 
579, 581, 584, 1859. (After Koch, Erichson, and Lereboullet.) 
Astacus torrentium (Steinkrebs), Kionztycrr, Jahresh. Vereins vaterlindl. Naturkunde Wiirttemberg, 
XXXVIII. Jahrg., p. 340, 1882. 
Astacus torrentium, Faxon, Proc. Amer. Acad. Arts and Sci., XX. 158, 1884. 
Koch’s A. saxatilis, A. trist’s, and A. torrentium are without doubt one and 
the same species, equivalent to A. ¢orrentium (Schrank) Wolf. According to 
Koch, A. sazatilis is distinguished by a slightly carinated rostrum, whereas 
in A. ¢ristis and A. forrentium the rostrum is not carinated ; but Erichson, who 
examined Koch’s types, tells us that there is an indication of a median ros- 
tral carina in A. ¢ristis and A. torrentium also. The carina is certainly shown 
in an exaggerated form in all of Koch’s figures. The dark color of A. ¢r7stes 
came from a coating of mould, according to Erichson, and the broad abdo- 
men is simply a sexual character. 
