XXXVl INTRODUCTION. 



naked ; toes four in number, the third and fourth connected at their base by 

 a membrane ; the hind toe touching the ground at the tip (p. 621). 



LlMOSA, Brisson. — Bill very long, rather thick at the base, compressed, slightly 

 curved upwards ; both mandibles grooved laterally to within a short distance 

 of the point, which is somewhat dilated and blunt ; tip of the upper 

 mandible projecting beyond the lower one. Nostrils basal, placed in the 

 lateral groove, narrow and longitudinal. Wings pointed, of moderate length, 

 the first quill the longest. Tail short and even. Legs long and slender, a 

 great part of the tibia naked. Three toes in front, one behind ; outer 

 and middle toes united at the base by a membrane, the inner toe nearly 

 free ; middle claw dilated, recurved, and pectinated ; hind toe short, and 

 articulated fairly high upon the tarsus (p. 623). 



NuMENius, Brisson. — Bill long, slender, and decurved to the point, which is 

 hard ; upper mandible rather longer than the lower, rounded near the end 

 and grooved along three-fourths of its whole length. Nostrils lateral, linear, 

 pierced in the groove. Wings moderate, the first quill the longest. Legs 

 rather long, slender ; tibia partly naked ; three toes in front, united by a 

 membrane as far as the first joint ; one toe behind, articulated low upon the 

 tarsus and touching the ground (p. 627). 



Order GAVI.^. 



Family LARID.F:. 



Bill without a cere ; sternum with two notches on each side of the posterior 

 margin ; toes partially or fully webbed ; claws feeble or moderate. 



Subfamily Sterxi.n'^. 



Hydrochelidon, Boie. — Bill about as long as the head, nearly straight, tapering. 

 Wings long and pointed, the first quill the longest. Tail short, very slightly 

 forked. Legs short ; the tibia bare for some distance ; the tarsus compressed, 

 anteriorly scutellated ; three toes in fiont connected by deeply scalloped webs ; 

 hind toe small and elevated ; claws long, slender, curved (p. 633). 



Sterna, Brisson. — Bill longer than the head, nearly straight, compressed. 

 Wings long, pointed, the first quill-feather the longest. Tail distinctly forked 

 in varying degrees. Legs slender, naked for a short space above the tarsal 

 joint ; the three toes in front united by membranes which are concave in 

 front or semi-palmated ; hind toe free ; claws curved (p. 639). 



Angus, Stephens. — Tail moderately long, rounded, slightly emarginated. Three 

 anterior toes united by a very full web, hind toe small ; claws strong and 

 curved. Otherwise much as in Sterna (p. 655). 



Subfamily LARI^■.^•:. 



Xema, Leach. — Bill rather shorter than the head, moderately stout ; the upper 

 mandible decurved from beyond the nostrils to the tip, the gonys angular 

 and advancing upwards. Nostrils basal, lateral, linear. Wings long, the 

 first quill the longest. Tail distinctly forked. Legs moderately long ; the 



