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BULLETIN OF THE BUSSEY INSTITUTION. 325 
evidently been voided and from the general appearance of the frag- 
ments I supposed, at first, that the stones were most probably 
those of the wild species (Prunus serotinu and P. virginiana), the 
so-called black and choke-cherries, which are common enough in 
this vicinity ; though it was recognized at. once as almost equally 
probable that some of them were stones of the mazzard-cherry, 
which is also well represented in this neighborhood. The question 
was readily solved by comparing the fragments in the dung with 
broken stones both of the wild and the mazzard-cherries which my 
colleague, Mr. B. M. Watson, Jr., was kind enough to procure for 
me. On making this comparison it appeared at once that the 
stones both of the wild and of the cultivated cherry were repre- 
sented in the dung, and that the larger part of the fragments in 
the dung were those of the cultivated cherry, — manifestly because 
of the greater hardness and thickness of these stones which hinders 
them from being ground to powder so readily as the much thinner 
stones of the wild-cherries. There was no lack, however, of frag- 
ments of the stones of wild-cherries; and there is no room for 
doubt that the pigeons had eaten indifferently the stones of choke- 
cherries. of black-cherries, of mazzards, and of such of the culti- 
vated varieties of cherries as may have been accessible to them. 
Immediately after finding the dung, in October, I searched for 
wild-cherries that might perhaps be still clinging to the trees and 
was rewarded by finding some six or eight examples of the choke- 
cherry adhering to fruit stalks which were still attached to the tree. 
Still later, on November 5, in a pasture adjacent to the grounds of 
the Bussey Institution, I found a couple of cherry-stones on the 
ground beneath a ‘wild black-cherry tree, thus proving that the 
stones were still accessible to the birds. On breaking the choke- 
cherry stones it appeared that the shells are almost as thin as those 
of the black-cherry (P. serotina), from which indeed they can 
hardly be distinguished by the naked eye. 
When the dung was discovered the question arose whether the 
pigeons might not have swallowed the stones accidentally, as it 
were, when eating the ripe fruit. The wild passenger-pigeon is 
known to be fond of many kinds of berries and probably eats the 
fruit of the wild-cherry, as fruit. But this idea seemed hardly con- 
sistent with the ordinary habits of the domestic pigeon, and it 
speedily appeared that there was really no ground for assuming 
that the birds had eaten any cherries, as cherries. It seemed most 
probable, on the face of the matter, that the cherry-stones had been 
