APPENDIX NN. 
1317 
is found all over the mountains, and in fall crosses the range, and is found but little 
less abundantly in Southern California. , 
Note.— The Zonotrichia leucophrys, though not noted by ns, doubtless occurs mingled 
with docks of the above bird, especially as it was found by us in Southern California. 
19. Zonotrichia coronata (Pall.).—Golden-crowned Sparrow. 
The great mass of these sparrows, in their journey southward, keeps on the western 
slope of the Sierras. It occurs, too, along the eastern spurs in fall, but, comparatively 
speaking, in very small numbers. 
20. Passerella iliaca (Merr), var. megaryncha Bd.—Thick-billed Sparrow. 
This appears to be the only Passerella occurring along the.eastern slope, where it is 
numerous in summer and fall, and where I believe it is resident. 
In a recent report (1870) I was led to combine the present bird with P. schistacea, 
separating them from the P. townsendi and iliaca mainly on the strength of the differ¬ 
ent proportions. Subsequent examination, however, has convinced me that the genus 
is represented by but one species, and that the three western forms, townsendi, schistacea, 
and megaryncha are but varieties of one and the same species. These under different con¬ 
ditions of climate have become more or less differentiated from the original type till they 
represent well-marked geographical races, the intergradation of which with each other 
and with iliaca it is perfectly possible to show. As noticed in an earlier part of this re¬ 
port, all specimens of the variety megaryncha from the eastern slope of the Sierras show 
very decided intermediate characters between the extreme condition this form assumes 
in the Coast Range and the P. schistacea from the interior, a fact to be expected from the 
half-way position of the region. A series connecting the two may very readily be 
formed. An examination of the material in the Smithsonian, much of which was col¬ 
lected by the expedition, enables us to speak with equal confidence of the close rela¬ 
tionship existing between schistacea and townsendi. Specimens connecting the two in 
a very complete chain may easily be selected. Hitherto no specimens intermediate 
between iliaca and townsendi have been met with, and though the differences separat¬ 
ing them have been chiefly modifications of color only, differences of degree of intensity 
and not of pattern, this has been deemed sufficient to keep them apart. 
It will be remembered that the habitats of the two are, in the northwest, in close 
juxtaposition to each other, iliaca being one of quite a number of eastern birds that 
in the north find their way across the continent and reach Alaska. Townsendi, with its 
summer homo in the northern portion of the Pacific province, also reaches Alaska, and 
it is probable that here the two forms come together. At all events, a series of sixteen 
specimens collected by the expedition in California, in 1875, presents unquestionable 
evidence of the intergradation of the two. Of these I do not find one which compares 
exactly with the usual style of townsendi, as it appears in specimens from Kodiak, 
Sitka, etc. The one extreme of this series exhibits quite a close approach to the dark 
olive-brown of townsendi , with its uustreaked dorsum ; the other in its light condition 
quite suggests the ferruginous style of coloration.of iliaca ; such specimens have the 
back obsoletely streaked. One other specimen from California in the Institution so 
closely approaches iliaca that it was so labeled, and supposed in the absence of others 
showing its true relation to be a straggler of this species. In connection with the 
above suite its position as one of the series showing the intergradation of the two 
forms is readily seen. 
The following measurements illustrate the relations, in size, the four forms bear to 
each other: 
P. iliaca: Wing, 3.40; tail, 3.07 ; bill, .32; tarsus, .93; (average of ten specimens.) 
P. townsendi: Wing, 3.20; tail, 3.15; bill, .49; tarsus, .94; (average of twenty-three 
specimens.) 
P. schistacea : Wing, 3.13; tail, 3.37; bill, .44; tarsus, .91; (average of nine speci¬ 
mens.) 
P. megaryncha : Wing, 3.21; tail, 3.58; bill, .51; tarsus, .93; (average of eight speci¬ 
mens.) • 
As will be seen from the above measurements, schistacea and megaryncha agree in 
having the tail considerably in excess of the wing; while in iliaca and townsendi the 
wing exceeds the tail. In townsendi, however^ this discrepancy in favor of the wing is 
very slight, and, indeed, in some few specimens the two are equal, or the tail may even 
bo slightly in excess of the wing. It would appear, therefore, that in respect to the 
relative size of these parts, townsendi indicates the first step in the variation, which is 
seen to be more marked in schistacea, and to find the limit in megaryncha. 
One unexpected fact shown by these measurements is, that not only does an increase 
in length of tail take placo in the three western varieties, a variation shown in other 
species, whose habitat extends from the eastern into the western province, but a de¬ 
crease in size of wing. The different proportions which ensue come, then, from two 
