56 (iEOGKAlMIICAJ. DISTK IBl TIOX. 



M. Fischer coiu-ludes. - Is tin- doctrine of evolution ovci'- 

 tliruwn by the facts M. BnrniiMle Ims pnxlucedr I iU> not tliiniv 

 it. He has proved that tliere existed anioiio- the ancient ceph- 

 alopods two great types, wiiicii liave continned separate diiriuL;' 

 the entire period of their existence ; bnt the evohition of encii 

 of these types remains extremely i)robable, and conforms to 

 observations made upon them. In such matters one cannot, in 

 etiect, ask more than a {)robability.'" * 



Geogra'phical Dislrilndion . 



Most of the spi'cies (jf Octopods and the Nautilus are 

 littoral in liatiit. and linvc thence Iteen conjt'ctnrctl to I'njoy 

 but a limited dist rilnition : and which is held to justify the 

 niulli|ilic;ition of species. This reasoning- is, however, falla- 

 cious, as it is well known that many litioral moUnsks. ncjt 

 nearly so wi'U provided Avith means of swimmin<i-. have be- 

 c-ome world-wi(h' in distribution. I slcdl show hci'eid"tei\ not 

 only that particular species of Octopus are known to inhabit the 

 sliores of distant conntries. bnt that a large i)roportion of these 

 si)ecies which have been distinonished by slight and mutable 

 characters, and by their geograi)hical distril»ution. will j)robably 

 need to be united when sntliciently s' ndicd. This probal)h' ex- 

 tensive disti'ibntion of living littor.'d species cories[)onds with 

 observations made upon fossil species of .Vmmonites. Nautilus 

 and other chaml)ered genera. Avhich are ])r()ved to have been 

 littoral in habit by their occui-rcnce only in deposits repivsenting 

 ancient sea-shores. Not io multiply exami)les amongst these 

 fossils, it may be mentioned that Nautilus simplex oecnrs in 

 Kuiope, East Indies and Texas; that Ammonites Botomagensis 

 is found in Kuroi)e, East Indies. X. and S. Africa and S. 

 America; and that Baculiles anceps had even a greater distribu- 

 tion. Nevertheless, temi)erature has l)een observed to have 

 some elfect upon the distribution of the living octopoda of 

 Kurojx'. simihii- l»ut distinguishable forms ov species inhabiting 

 its northern seas, fi'om those of the Mediten-anc:in. As in Afol- 

 Inscan life generally, the development of speciiic forms has been 

 greatest in tro})ical waters. 



Jour, de Zool, iv, 419, 1877. 



