ASTAITS. 143 



Aatacus pitllip *, LKRKKOri.l.KT, Man. S,.c. Sri. Nat. Slraslimu-, V. 7 (vp:,i'air pri-mati'in), I'l. II., Ill 



figs. :>-:i'i, is.-,s. 



M/<i,-its pulli/,,:*, viu-. .//,/<,-., l,i:i;i:i!nri.i.KT. Mnu. Soo. Bei \:ii Sira-lioni-.:, V '.I, K",s. 

 Ax/ili'H* l,,,;;;,/ii<,,, (_S| rin kivl I (ML part I, III KMI I l.nr, VI, 'in. \r ,,l I mprr. Sri Si I 



1859. 



.Win-it* x,i.i;/f/'i*, (lltritK, Kin \u-l!n<_' n;irh Trirst mid ilcin Qnarnrro, |i ?:i, 1M1]. 



A.if,/,-//.i sHj-n/ilh, llKi.i.ni, DM: Crustacean drs Mhllich.-n Europa, i>. 217, Tai'. \ II. figs. 3, 5, 1803. 



Axtdi-nsfriitiniiHs (IVnvvissi- :i pii-ils blaiir-), < '.MtiioxxiKK, I,' l : >rr\ i^sr, | P . s, Isii'.l. 

 Potamobius astacus, (i. IV So\\ i:iiitv, ('uiitiiiUMlioii of Jjeacli's M;ilan>slr:u-:i l'.n|.i|,lil li^ilin.-i 



XVIII., XIX., Tab. XXXIV. li-. 1, L875. 



j*/,t<-i<sjlttri,t/ilis, HUXLEY,* Tliu Cnivlish, l ,,,.^i,,i. ami ].. .>:',( I in parlicnlar, Fnni(ix]jicec ami figs. 1-C,0 

 1380. 



ii-ivH/inni, HrxLEY,* up. ,-if., ]i. x".iG, fig. 61, A, n, (., lii;. i\->, \, n, 1880. 



jii/f/i/i -x (cli-r Dohlciikrclis), KI.UXZI.XGEK, Jalnrsh. V<'irins vatcrliiiul. Naturkiimlr \\'nrttri, l 

 XXXVIII. Jahr-., p. :m, 18S2. 

 i jiit/lipM, i'.vxoN, Proc. Amcr. Acail. Arls ami Sci.. XX. 154, 1884. 



Under the name "' Steinkrebs " the older authors appear to have con- 

 founded A. torrcntium and A. jil/ij>cs. Tliey were first scptirak-d as distinct 

 species in 1858 by Lereboullet with the names .4. loiii/irnrn/x and .1. /MtHl/ir*. 

 Gerstfeldt (1859) seems to have had very little material from without tin- 

 bounds of the Russian Empire. Of the "Steinkrebs" he had seen only li vi- 

 m-preserved dried examples from the Rhone, which, as appears from his 

 description of them (p. 577), belong to A. i(llqn *. He considers them to be 

 the same species as that described by Schrank and Koch, i. e. A. torrntliinn. 

 Compared with A. torrcittiiiiii, A. pallij>e>s has a narrower rostrum with a 

 longer and narrower acumen; the median keel is more evident, especially 

 near the tip of the rostrum; the antenna? are shorter, and the peduncle ot 

 the antennae overreaches the tip of the rostrum by only a small fraction 

 of the length of the terminal segment, while in A. torrcnliinii it surpasses the 

 rostrum by the whole length of the terminal segment; the longitudinal ridiie 

 on the lower face of the antennal scale is not toothed, as in A. torrentium : 

 behind the cervical suture are several lateral spines; the cheke are innn- 

 coarsely and sparsely tuberculate. For a detailed comparison of these t\vo 

 species, see Klunzinger, oj). cit. 



A. pallipes and A. tormi//i/i>i have a rudimentary pleurobranchia on t.-;n-!i 

 side of the penultimate and antepenultimate somites. In all the other 

 species of Astacus which I have examined there is a third pair on the preced- 

 ing somite. The first abdominal appendages of the male A. fiof/i/ir* are 

 figured by Brocchi, Ann. Sci. Nat., G e Ser., Zool. et Paleontol, Tom. II.. I'l. 

 XIII. figs. 12, 13 ("Astacus fluviatilts" from Vaucluse). They agree in form 



* Huxley leaves the question of tlie specific or the varietal value of the forms A. n 

 fium (= A.fiiciatilis and A. imHipi'i) undecided. 



