The Ohio ^J^aturalist, 



PUBLISHKD BY 



The Biological Club of the Ohio State Uni'versity, 

 Volume XIII. JANUARY. 1913. No. 3. 



TABLE OF CONTENTS. 



Banta and Goetner— IiKhieed Modifications iu Pigment Develoimiont in Spelerpes 



Larvae 49 



GORMLEY— The Violets of Ohio 56 



Mark — Notes on Ohio Moses 62 



C'LAASSEN— List of Plants Collected in ("nyahoga County and New to this County 

 or to Ohio 64 



INDUCED MODIFICATIONS IN PIGMENT DEVELOPMENT 



IN SPELERPES LARVAE.* 



(Preliminary Paper) 

 A. M. Banta and Ross Aiken Gortner. 



(From the Station for Experimental Evolution, The Carnegie Institution: 



of Washington.) 



Introduction. 



We present here a brief account of a series of experiments 

 having as their aim the inhibition, or the modification of pigment 

 development. 



We beheve that it is a fairly well established fact that the 

 black melanic pigment results from the interaction of an oxidizing 

 enzyme of the tyrosinase type and some oxidizable chromogen, 

 the exact nature of which has never been elucidatedf. One of us, 

 (Gortner 1911, b,) has shown that certain organic phenols inhibit 

 the action of tyrosinase in the test tube and the suggestion was 

 made that perhaps certain types of colorless animals owe their 

 lack of pigment to the presence of inhibitory compounds. The 

 present series of experiments was carried out in order to test the 

 inhibitory powers of the m. di-hydroxy phenols in vivo as contrasted 

 with their action in vitro. 



The material upon which the experiments were carried out, 

 consisted of eggs and embryos of the salamander, Spelerpes 

 hilineatus, Green. This material is unusually suitable for such 

 work inasmuch as the eggs contain no pigment when deposited, 

 and the early stages of pigmentation in the embryo can thus be 

 followed from day to day. 



* Presented at the annual meeting of the Ohio Academy of Science, 

 Columbus, Nov. 30, 1912. 



t For literature see Kastle (1910), Riddle (1909), and Gortner (1911, a). 



,^i ^•^ V.-g 



"I 



L I B R A R Y 33 



