TURDUS. 25 
olive. Beneath pale grayish fulvous, rather darker on the flanks, 
where the color is much as on the back. Belly to crissum white. 
Chin white, the feathers streaked centrally with blackish brown; a 
whitish region posterior to the streaks. 
Axillars yellowish fulvous, as also to a rather less degree, the in- 
side of the wings, including the basal portion of inner webs of the 
quills. Bill and legs horn color, the under mandible paler. 
Length, 8.75; wing, 5.20; tail, 4.30; bill to nostril, .57; tarsus, 
1.20; middle toe and claw, 1.12; claw alone, .80; longest primary 
exceeds the shortest by 1.20; second quill intermediate between the 
6th and 7th (.16 longer than the latter). 
This specimen, in color of upper parts, wings and tail, is very 
similar to Turdus gray, although readily distinguishable by the 
white abdomen, darker throat-streaks, ete. 
Turdus leucauchen is distinguishable at a glance from 7. assimi- 
lis, by its colors, almost black above, not fulvous; light plumbeous 
ashy beneath, not pale fulvous; uniform brown of inner webs. of 
quills, and dark axillars, not decidedly paler and fulvous; greater 
amount of white on the throat; yeltow bill; shorter and more 
rounded wings, etc. 
I have been thus detailed in showing the differences between what 
I consider characteristic specimens of assimilis and leucauchen, to 
introduce a series of specimens exactly intermediate between the two, 
all labelled asstmilis: 18,564 from Orizaba, by Dr. Sclater ; 30,648 
from Guatemala, by Mr. Salvin; 22,357, Mexico, by Mr. Verreaux. 
In 22,351, the size, proportion, and color are more like lewcauchen ; 
the wings and tail are nearly as dark; the back, however, is green- 
ish-olive; the under parts similar, but paler; the axillars with a 
little more fulvous; the bill is as yellow. In 18,564, the relation- 
ship to assimilis is shown by a still lighter tinge above, the axillars 
almost as fulvous as in assimilis. Some dark shaft spots and streaks 
in the feathers of the breast are indications of a certain degree of 
immaturity. 
The gradation of these specimens between assimilis, as described 
above, and leuwcauchen, is so perfect, that in coloration No. 18,564 
‘would, I think, be referred to the former, and 22,357 to the latter. 
With this, No. 30,648, from Guatemala, recently. received from Mr. 
Salvin, also agrees quite closely—the axillars only being rather more 
fulvous. 
It is quite possible that these specimens referred to as intermedi- 
ate forms may, as labelled, all belong to Zurdus assimilis ; while 
22,351 may be another species. In this case I must leave the 
