Miscellanea 
257 
(ii) That while tlie American egg is more variable in shape than Bumpus' English series, 
it is less variable than mine, although the difference between the two is really not significant. 
(iii) That the American egg is sensibly shorter than the English egg, if judged by either 
English series. 
(iv) That the American egg has probably slightly less breadth than the English egg. 
(v) That having considerably less length and only slightly less breadth, the American egg 
appears rounder than the English egg. 
English Eggs 
American Eggs 
Character 
Pearson (687) 
Bumpus (868) * 
Bumpus (868) 
Mean Length ... 
S. D. Length ... 
C. of V. Length 
21 -8229 + -0456 
1-1946 + -0322 
5-47 
21-7368 + -0362 
1-0677 + -0256 
4-91 
21-3065 + -0356 
1-0481 + -0252 
4-92 
Mean Breadth... 
S. D. Breadth ... 
G. of V. Breadth 
15-5052 + -0200 
•5245 + -0141 
3-38 
15-3683 + [ ? ] 
[ ? ] 
[ ] 
15-3443 + [ ? ] 
[ ^ ] 
[ ? ] 
S. D. Index , 
71-2160 + -1433 
3-7560±-1013 
70-8662 + -1092 
3-2155 + -0772 
72-1843 + -1250 
3-6831 ±-0884 
If we put aside Professor Bumpus' colour and shape appreciations t, I think we must conclude 
from the actual measurements that there is no evidence that the American egg is more variable 
than the English egg. On the contrary it appears slightly less variable, as we might expect if 
the sparrow imported into America had been largely drawn from one district of the mother 
country. In the next place the American egg does appear to be -5 mm. shorter than the English. 
This might be due to (a) direct selection in America, or to {h) absence of the periodic selection 
we may suppose to maintain the stability of the species in England. But it may equally likely 
be due to original import into America of an English local race, to good or bad seasons in 
England or America in the year the eggs were collected, or to a large preponderance of second 
nestings in the clutches measured by Professor Bumpus. All these points could, I think, be 
investigated and answered. Professor Bum2)us has opened a most interesting field of inquiry, 
and for the next few years an-angements ought to be made for the annual measurement in both 
America and England of good series of sparrows' eggs, with due record of district, probable 
nesting and climate of previous winter and spring. We might then learn the effect of each 
of these factors in both America and England, and at least ^^ut on record valuable results for 
comparison with similar measurements 20 or 30 years hence. Only in this way shall we be 
able to ascertain whether there are persistent sources of differentiation at work. 
K. PEARSON. 
* I could find only the indices of 867 English eggs given. 
t The extraordinary variety of mottling and tint on my eggs was commented on by all who saw 
them; I consider that it varied a good deal with the district. I found no method of quantitatively 
measuring it. It disappeared to some extent with time and I daresay something of the colour would 
be liable to fade if the eggs were preserved for any time and transported. 
Biometrika i 
25 
