XTI. Ox THE Antiquity of the Caverxs axd Cavern Life of the Ohio Yallet.i 



By N. S. Shaler. 



Read Decemljcr 2, 1874. 



Introduction. 



yAVERN animals, nhvavs interesting, have acquired an importance quite unexpected by 

 then- hrst students smce the questions concerning the origin of organic si^ecies assumed 

 the.r present shape. Whenever we find any animal, especially a highly organized form, 



iving m the perpetual darkness and uniform temperature of a cavern, we are entitled to 

 look for somethmg which marks its departure from the usual conditions of life. If or-anic 

 forms are the dn-ect product of their environment, then the change from the sunlit imper 

 world to the cavern conditions must lead to modifications of the most important character. 

 These changes have, in fact, been found, and as a general rule they most affect those parts 

 of the bodywhich are the most directly concerned with the phenomena of the outer world 

 Organs of sight, or organs which may replace sight, are the most affected. We see here 

 orgairs like the vertebrate eye, which traces its development down all the infinite acres to 

 the Silurian or more ancient seas, fading like a shadow in this darkness. Amono- insects 

 where the visual organs are essentially as complicated, and date their origin from a time 

 almost as remote as the vertebrates, we have the same marvelous change, though the 

 known and interminable variation amongst this class of animals makes the phenomena less 

 striking. Ihese changes must be studied in their detail before we shall know their full 

 value. There is one other point, however, to which attention must be called before we 

 come to the mam object of our study, viz., how far is this hidden life connected with the 

 life of the_ outer world in the same neighborhood. Collections formed for the special purpose 

 of determining tins point have already been made by the officers of the Kentuckv Geological 

 burvey and ni time it is hoped they may afford the means for specially discussing the mat- 

 ter of the affinities of the several species found in the caverns to the outside forms At 

 present it suffices to anticipate the special study by the statement, already warranted by 

 the investigation of these forms of life in other regions, that there is in mast cases a close 

 connection between the life within our caves and that in the neighboring country .= If 



^ Tl.is paper i. publl.he.l in accord.ance with the provision = I am greatly indebted to my friends and fellow worker. 



iourna-trZetr, 1^ :!■".!">; -■'■"'■!^'^ 'r\'^ '"'^ ™--'-" -^-^ "-' refer the reader to their 



ioiiniil in arlvnn,.,. nf tl,„ ^„ i >-uiieiuMuii, anu mnst reler the reader to the r 



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these cavern species. 



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