2 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



processes usually present (absent in CEdicnemi, Cursorii, Chionides, 

 and Alcae); supraorbital grooves usually present (absent in some 

 Limicolge); lachrymals firmly united with prefrontals; occipital 

 fontanelles usually present (absent in Jacanida?, Dromadidae, and in 

 adults of Lari); coracoids with a subclavicidar process; coraco- 

 humeral groove distinct; furcula U-shaped, with a hypocleideum; 

 spinse sterni short, separate; cervical vertebrae, 15-16; dorsal ver- 

 tebrae, 5-8; no ankylosed dorsal vertebrae; hasmapophyses of cervical 

 and thoracic vertebrae opisthocoelous, only 1-2 vertebras with two 

 fairly closely approximated haemapophyses for reception of the 

 carotid arteries; hallux (if present) connected with the flexor longus 

 hallucis, never with the flexor perforans digitorum; anterior toes 

 completely cleft to completely webbed; hypotarsus complex (with 

 canals in Limicolae, with 2 grooves in Lari) or simple (Alcae) ; flexors 

 of Type I; thigh-muscle formula variable; biceps slip to patagium 

 usually present (absent only in Rynchopidae); caeca usually large 

 (rudimentary in Alcas and some Limicolse); carotid arteries, 2; 

 rhamphotheca usually simple (complex in Chionididas, Stercorariidae, 

 and some Alcaa); crop absent (except in Thinocorythes) ; intestinal 

 convolutions of Type I (peri-orthocoelous with mesogyrous tendency) ; 

 syrinx tracheo-bronchial, with 1 pair of muscles; oil-gland tufted; 

 cervical pterylosis with lateral apteria; dorsal pteryla well defined 

 on neck, forked on upper back; aftershaft present; primaries, 11 

 (1 minute and concealed); secondaries, 11, aquincubital; rectrices, 

 10-28; downs on adults present; young ptilopasdic, nidifugous 

 (Limicolae) or pseudo-nidifugous (Lari and Alcae). 



KEY TO THE SUBORDERS OF CHARADRIIFORMES. 



a. Haemapophyses of dorsal vertebrae less developed; coracoid with a subclavicular 

 process, the ectepicondylar process well-developed (except in some Lari); ster- 

 num relatively short and broad, the metasternum not rounded and not projecting 

 beyond the postero-lateral processes; clavicle connected with both praecoracoid 

 and acrocoracoid ; pelvis not laterally compressed; first digit of manus present; 

 thigh-muscle formula with Y, usually with B, the ambiens absent only in Ryn- 

 chopidae; biceps slip not distinctive; tensores patagii not distinctive; intestinal 

 convolutions of fewer loops (less than 6); dorsal pteryla interrupted between 

 anterior and posterior parts; caeca present, usually large (except in Jacanidse?); 

 wings long, the flight buoyant and prolonged; legs inserted near middle of body. 

 (Laro- Limicolae.) 

 b. Hypotarsus complex (with canals); coracoids separated (except in (Edicnemidae 

 and Jacanidas); supraorbital glands absent or small; basipterygoid processes 

 usually present (absent in Dromadidae, (Edicnemidae, Glareolidae, Chionididae 

 and Thinocory thidae) ; occipital foramina present (except in Dromadidae, 

 (Edicnemidae, Glareolidae, Thinocorythidae, Jacanidae, and Chionididae); 

 furcula without hypocleideum; adult downs on pterylae only; bill and tarsus 

 relatively long and slender; anterior toes iisually cleft to base or only slightly 

 webbed (fully webbed only in Recurvirostridae, part); young typically nidi- 

 fugous; habits limicoline or pratincoline, or if aquatic (Phalaropodidae) toes 

 not webbed but scalloped or lobed Limicolse (p. 3). 



