NOTES AND QUERIES. 31 
distinct types. The majority of writers are in error in regard to the 
number and description of these types, some of which are omitted 
altogether, or very inadequately described, Seebohm and Charles Dixon 
alone mentioning and accurately describing them, though Seebohm 
only figures two. They are well figured in ‘ Oologia Universalis Pale- 
arctica, George Thrause, part v., and in ‘ Higgs of the Birds of Europe,’ 
H. E. Dresser, part viii. In the latter splendid work they are beauti- 
fully figured, but unfortunately Mr. Dresser has apparently left out the 
buff type. They are: (1) pure white to pale yellow; (2) palest pink to 
rich salmon ; (3) pale green to greenish white; (4) pale brown to rich 
buff. I have placed them in the order to which they occur numeri- 
cally. No. 4 type is the one to which I refer as having been in- 
accurately described or omitted altogether, chiefly, no doubt, owing to 
its rarity. For the present purpose I have thought it sufficient to 
refer only to the ground colour, which is, to my mind, the most im- 
portant and only correct way of distinctly separating the types, not 
only of this species but of nearly, if not all, others. Now, it is quite 
obvious to me that the bird spoken of by Mr. Mussel-White as having 
produced the grey type in 1906 was not the same bird that produced 
the red type in 1907. Were his contention right, would he claim 
that in 1908 this bird would produce another type ?—say, the green 
type—and finally, in 1909, it would produce the buff type, thus having 
produced the four types in four consecutive years. Now we come to 
the crucial point—is the bird to commence producing these four 
types over again, which it should be expected to do if Mr. Mussel- 
White’s theory be correct ? This is, | think, most improbable and 
quite contrary to the accepted rule of Nature. Iam quite convinced 
in my own mind that the one type is perpetuated by one female (even 
though she may change her mate)—at least, all the evidence I have 
accumulated points in this direction—and the more experienced I 
become in the science of oology the more convinced I am, every 
season bringing fresh evidence in support. I will quote one case in 
point which has helped that conviction (in addition to the one 
already quoted). In the spring of 1906 I received from a corre- 
spondent in North Devon three eggs of the Tree-Pipit (A. trivialis) 
of a most uncommon variety, intermediate between the red mottled 
type and the red spotted or blotched type, which I had never seen 
before among the great number of clutches brought to my notice. 
This year I received, from the same correspondent and locality, a 
clutch which is identical in every respect and cannot have been pro- 
duced by any other than the same bird. Speaking of eggs generally, 
