BIRDS OF NORTH AND MIDDLE AMERICA. 449 
Characters possessed in common by the Lari and the Limicol, as 
opposed to the Alcew, are given on pages 2 and 3. Those possessed by 
both the Lari and the Ale but not shared by the Limicole are as 
follows: ; 
Hypotarsus simple (without canals); supraorbital grooves large; 
bill and legs relatively short and stout; anterior toes fully webbed 
(with a few exceptions); young tardily nidifugous (nearly nidicolous) ; 
habits aquatic. 
The Lari are long-winged swimming birds, of graceful, bouyant, 
and powerful flight, with anterior toes more or less fully webbed, the 
hallux small and elevated, sometimes rudimentary or nearly obsolete, 
and the legs are attached near the middle of the body, which therefore 
assumes a nearly horizontal position when the birds are standing or 
perching. Their nidification is not materially different from that of 
the Limicole, but the young remain longer in the nest than those of 
the latter group, being, in fact, more nidicolous than nidifugous. 
Distribution, cosmopolitan. 
* 
KEY TO THE FAMILIES OF LARI. 
a. Ambiens muscle and biceps slip absent; tendons to ulna side of arm, 2; bill pecu- 
liar, the mandible much longer than the maxilla, both excessively compressed. 
Rynchopide (p. 449). 
aa. Ambiens muscle and biceps slip present; tendons to ulna side of arm, 1 or none; 
bill not peculiar. 
b. Ramphotheca simple (bill without cere); caeca rudimentary (except in genus 
Gygis of Sternide); metastermum 4- notched; coracoids in contact; claws mod- 
erately to feebly developed. 
c. Thigh-muscle formula with B (except in Gygis),; expansor secundariorum absent 
(except in Anous); exposed culmen at least one and one-fourth (sometimes 
nearly three times) as long as tarsus, the latter usually less than one-tenth 
(never much more than one-ninth) as long as wing; tail usually (often 
deeply) forked; pterylosis typically charadriine...........Sternide (p. 458.) 
cc. Thigh-muscle formula without B; expansor secundariorum present; exposed 
culmen less than one and one-fourth times as long as tarsus (usually shorter 
than tarsus), the latter more than one-tenth (sometimes more than one-sixth) 
as long as wing; tail usually truncate or slightly rounded, rarely graduated , 
never very deeply forked; pterylosis not typically charadriine. 
Laridze (p. 561). 
bb. Rhamphotheca complex (bill with a cere); caeca well-developed, long; cora- 
coids separated; metasternum 2-notched; claws large, strongly hooked, 
BNALD Ae twit eedoche pes beear eran eame een enenamenes Stercorariidze (p. 676). 
Family RYNCHOPIDA. 
THE SKIMMERS. 
=Rhynchopsine Bonaparte, Geog. and Comp. List Birds, 1838, 60. 
=Rhynchopine LawRENcE, in Baird, Rep. Pacific R. R. Surv., ix, 1858, 837, 865.— 
Carus, Handb. Zool., i, 1868, 362.—Cousgs, Proc. Ac. Nat. Sci. Phila., 1869, 
314; Key N. Am. Birds, 1872, 323; 2d ed., 1884, 734, 772; Birds Northwest, 
1874, 712.—SciateR and Savin, Nom. Av. Neotr., 1878, 147.—Srrsneazr, 
Standard Nat. Hist., iv, 1885, 83, in text.—Gapow, in Bronn’s Thier Reich, 
40017—19—Bull. 50, pt 8— —30 
