584 Mr. C. F. M. Swynnerton on 



had been pulled out and were lying, damaged but now 

 neglected, beside it, while the rat had returned to the empty 

 shell of the Amblyos2nza egg, and was assiduously licking 

 out its inside. Returning three or four times I every time 

 found the Macronyx egg and its extracted contents lying 

 untouched, the rat close to it but completely ignoring it. 

 I therefore added a second, only slightly set Maa^onyx 

 egg from the second clutch, opening it slightly as usual. 

 This was as persistently ignored as the other, so I added an 

 egg, just slightly set, of ChalcopeUa afra (from the same 

 clutch as yesterday). This was also persistently ignored 

 (it may, of course, have been tasted in my absence), and after 

 two or three visits I removed the fresher Macronyx egg 

 and pushed the other slightly away, leaving the Dove's egg 

 alone just under the rat's nose. He still refused it^ so two 

 or three visits later I placed beside it an e^^ of A. aVnfrons, 

 very slightly set. This was at once taken and eaten. I 

 placed the fresher Macronyx egg beside the Dove's, and both 

 were now persistently ignored. I replaced the Macronyx 

 egg by one of H. jamesoni (spotted blue) and the latter's 

 contents were at once completely eaten. I again inserted 

 the fresher Macronyx egg, and it and the Dove's continued 

 to be neglected. I placed beside them a fresh C. ardens 

 egg and went away for twenty minutes. Returning I found 

 only the Whydah Bird's eaten. The hard-set Macronyx egg 

 and its embryo had been lying conspicuously a little to one 

 side throughout the experiment, and remained untouched 

 not only up to this point but about twenty minutes later 

 still, when I removed it. 



Later. — To-night I am again giving the rat water-made 

 maize-porridge only — no animal food. The idea is to see 

 whether it will affect his discrimination to-morrow. 



Preferences shown {very decidedly) : 



1. Amblyospiza albifrons, Hyphantornis jamesoni (spotted 

 blue), and Coliuspasser ardens. 



2. Macronyx croceus (both hard-set and nearly fresh), 

 ChalcopeUa afra (nearly fresh). 



Expt. 10. Feb. 7, 10 a.m. — No food since last night's 



