BIRDS OF NORTH AND MIDDLE AMERICA. 239 
as long as wing, slightly graduated, the four middle rectrices abruptly 
longer than the rest, contracted distally, with tips narrowly rounded; 
rectrices 12. Tarsus shorter than middle toe with claw (but equal 
to or slightly longer than middle toe without claw), less than one- 
fourth as long as wing, continuously scutellate anteriorly and poste- 
riorly; bare portion of tibia very short (much less than half as long 
as tarsus), non-scutellate; lateral toes decidedly shorter than middle 
toe, the outer slightly longer than the inner; no web between middle 
toe and either of the anterior toes. : 
Coloration.—Proximal secondaries (next to tertials), tips of greater 
wing-coverts, lateral upper tail-coverts, and most of under parts 
(except anteriorly) white; rump, median upper tail-coverts, and 
middle rectrices dusky; rest of upper parts grayish, the feathers 
darker centrally and faintly glossed with purplish, in winter plumage, 
more or less variegated with rusty and black in summer; head and 
neck nearly plain brownish gray, the chest with feathers gray 
centrally broadly margined with white in winter, the head and neck 
more or less streaked and chest spotted or clouded with blackish in 
summer. . 
Range.—Northern portions of northern hemisphere. (Two species.) 
KEY TO THE SPECIES AND SUBSPECIES OF ARQUATELLA. 
a, Summer adults and young with little, if any, rusty or cinnamon-rufous on’ 
upper parts, the former without any dusky patch or extensive clouding on 
breast. (Northern Europe, northeastern North America, and northwestern Asia.) 
Arquatella maritima (p. 239). 
aa. Summer adults and young with much rusty or cinnamon-rufous on upper parts, 
the former with a conspicuous patch or extensive clouding of dusky on breast. 
(Arquatella ptilocnemis.) 
b. Larger and much lighter colored; wing averaging 126.5.in male, 129.2 in female; 
culmen averaging 30.4 in male, 33 in female. (Islands of Bering Sea, north 
of Aleutian chain; coast of Norton Sound, etc., in migration.) : 
Arquatella ptilocnemis ptilocnemis (p. 244). 
66. Smaller and much darker colored; wing averaging 117.6 in male, 120.2 in 
female; exposed culmen averaging 26.3 in male, 29.6 in female. (Com- 
mander Islands, Kamchatka; Aleutian and Shumagin islands, Alaska; 
coast of Norton Sound, Kotzebue Sound, etc., in migration.) 
Arquatella ptilocnemis couesi (p. 247). 
ARQUATELLA MARITIMA (Briinnich). 
PURPLE SANDPIPER. 
Adults in summer (sexes alike).—General color of upper parts 
dusky, the head and neck narrowly and rather indistinctly streaked 
with light buffy, the scapulars and interscapulars sooty black or 
blackish brown faintly glossed with bronze or purplish bronze and 
irregularly spotted or indented along edges with dull buff and nar- 
rowly margined terminally with whitish; rump, upper tail-coverts, 
