ONCHIDIUM AND THE QUESTION OF ADAPTIVE 

 COLOEATIONi 



LESLIE B. AREY 

 Northwestern University Medical School 



1. As the result of his extensive study of the phenom- 

 ena of coloration in the tropical reef-fishes, Longley 

 (1917) comes to the conclusion that the colors of these 

 animals are "correlated with tlioir hal)its in sueli a way 

 that their conspicuousness is tlicrcl)^ i-cduccd. Tlu re is 

 no correlation of bright colors willi s)M'ci;il inod.'s ni de- 

 fence, and no evidence tlint l)i-i<:lit-c(»!()i-.Ml 1\iir> enjoy 

 immunity .^Tentef 1li;ni tli;i1 of llu'ii- fellow^." The gen- 

 eral tendciic) ol l!ii^. 111.' iMo.t ivceiil. ;nul in n.:ni> \\;i>s 

 the most tlioroimli. olisei'xnt ioii;il >\\\i\y of the (|iicsiioii of 



f;ivoi-s ;i(lheiviiee 1o the \ iew th;it ns ;i Nvhoh' the eoh>ra- 

 tioil of ;niilliaU i^ of a c-o,ieraliim, heliee ;..l;il)ti\.-l\ pn)- 



tectiNe kind. There ai-e inMance. anion- inv ertel.rates 

 wliich seem fiiiKhaiiieiitally inconsistent with this inter- 

 pretation, heeausi' the oiuanisms in question are not 

 colored like tlieii' liahitiial background and because they 

 are for this, and foi' other iiide])endent n^isons not incon- 

 spicuous. It is also a tat-t that in specilie instances of 

 this sort special repnunatorial s\sTenis nre frtMjuently 

 encountered. Becatise of lis i iiiport ance for tlu^ theory 



tiii\-. I'lie natural hi>tor\ ot \\\r Iiltoi-;il pnhiionate On- 



