1878.] AND DISTRIBUTION OF THE CRAYFISHES. 753 



species of freshwater Astacidce and the marine genus Nephrons ■ " 



of] those of Astaeoides than these latter did from one another and 

 as, moreover the latter name had the priority, he proposed n'rovi 



,rZl 1 T T° U u un( l ues ti°»ably right both in denying any 

 special relationship between Paranephrops and Nephrons and in 

 asserting that the New-Zealand Crayfish differ less ifom Tome f tl 



sToTt. *5, gem , ,S If*** " itS limitS are at PresenT unde - 

 stood, than these do from one another. But I shall have occasion 



to show that the type of the genus Astacoides, the MadaS a 

 Crayfish, differs so widely from the other Crayfishes of the southem 

 hemisphere, that the latter cannot be included in the same genus 

 while Paranephrops is sufficiently different from the Australif n and 

 £HX!£? fi8heS t0 rCnder US reC °g niti - as * distinct generic 

 The distribution of the Crayfishes, so far as it is hitherto ascer 

 tamed, is not a little remarkable. Astacus fluviatilis occurs nvaHou 

 parts of England and in Ireland ; but I clnnot find any record"? i 

 n Scotland. Dr. M'Intosb, who has been kind enough to look into 

 this pomt in aid of my inquiries, assures me that Crayfishes are Sot 

 indigenous to that part of Britain, that they do not exS in "he 



the island of Mull failed ; they were placed in various streams 

 Jut none were ever seen again. Even in England, Crayfishes appear 

 to be restricted to certain rivers. They abound, for example inThe 

 Thames; but I cannot hear of any in the Cam or the Owe thoul 

 their absence in the latter rivers cannot be ascribed to any JS 

 ^calcareous matter in the districts through which thos/n™ 



Vifrty* ^ UViatU i S ' h TT' eXteuds a11 over the astern half of 

 Euro e ; as ftr g0 h ^ p g ^ ^ r ot 



Mediterranean ; while, eastward, it reaches Sicily, Northern Greece 

 and the western shores of the Black Sea. In Spain there appears 

 to be no doubt that it occurs about Barcelona ; but whether TL 

 found in the rest of the Spanish peninsula is uncertain \ 



and t°h BaTrt 5 n —"A ^^ ^ viatUis extend * to Sweden 

 and the Baltic provinces of Russia, and through Western Russia hv 

 thebasinsof the Dniester and the Bng, to the Black Sea ' 7 



Over this vast area, marked local varieties appear to be not un- 

 common ; and most authors agree to regard a Crayfish whch occurs 

 in Southern Europe, France, Switzerland, and Germany, and which 



In fluvfo lSTw T ; eUam ^ flUTiiS *»«*«* --niri ,,feru„ t Z g ores 

 in Ui vio Lyd w Haly cancros iuvenit Busbequius, Ep Turc i r> SO '- Z' 

 were these J,yd, au <• oancri " erayfiahes or fluviatile cmta ? P ' ' 



