Selection o/" Helix iiemoialLs /-// the Sony-Thruah. .029 



Table III. 

 Control Collection for comparison with Table II. 



Formula. Number. Per cont. of total. 



1L».'J45' 8 13G 



lL'.*i(4.'-.)» 3 6-0 



(li.').'i(4r,)« 1 17 



oo.-yo • 1 1-7 



]2:M0' 1 1-7 



0-2^00 * 1 1-7 



(X>.H(X)' 1 1-7 



(HXXK) (liMlula) " 4 ( j > . 



Vnrs. rubella and caxtanea .... 6 \ 



J£. cantiana 33 ^9 



Total .'■)9 



Section II. By Frances Pitt. 



At the request of Miss M. D. llaviland, I ol)taine(l a 

 young song-tlirusli in the spring of 11)18, and reared it l)y 

 hand, in order to ascertain wlu-thcr the thrush has a 

 preference for a particular variety of Hvlix neiniirulis, and 

 also if the habit peculiar to the thrush of breaking snail- 

 shells ou an "anvil" is instinctive or actjuired through 

 experience by each young bird. 



When the bird uas fully fledged I offered it two examples 

 of Helix nenioralis, of formulae 00000 and 12315 res|)ec- 

 tively. The thrush paid no attention to them unless tlicy 

 moved, and then it pecked at the jjrotruding tentacles until 

 the snails withdrew iuto the shells, after which the bird 

 ignored them. 



The experiment was repeated the next day, with the same 

 result, except that the bird pecked the shells sharply two or 

 three times. 



On the third day four snails were offered — two 12315 and 

 two 00000. This time, when the bird's attack caused the 

 snail to retract, the thrush turned one shell over, looked 

 into the cavity, and shook it vigorously before casting it 

 aside. 



At the fourth trial, two days later, five nemoralis were 

 offered — two 00000 and three 12345. This time the thrush 

 carried one of the former variety round the cage, and struck 

 it on the ground until it fell from his grasp, thereupon he 

 picked it up again and battered it on a stone. As it did not 

 crack readily, he seized each of the others in turn, and tried 

 in vain to hrcak them. Finally, he took the first snail 

 again, and idtiniately broke it open and ate it. 



From the foregoing observations 1 auj inclined to believe 

 that the only part of the snail-cracking habit which is 



