BIRDS OF NORTH AND MIDDLE AMERICA 



149 



Credscus Cabanis, Journ. fur Orn., 1856 (publ. 1857), 428. (Type, by monotypy, 



Ballus jamaicensis Gmelin.) 

 Crescicus (emendation) Cotjes, Check-list North Amer. Birds, ed. 2, 1882, 110. 

 Oreoiscvs (typog. error) Bbbwee, Proc. Boston Soc. Nat. Hist., xvii, 1875, 447. 

 Limnocrex Ridgway, Smiths. Misc. Coll., Ixxii, No. 4, 1920, 3. (Type, by 



original designation, Porzana dnereiceps Lawrence.) 

 Thryoorex Ridgway, Smiths. Misc. Coll., Ixxii, No. 4, 1920, 4. (Type, by 



original designation, Corethrura rubra Sclater and Salvin.) 



Small Kalleae (wings 70-85 mm.) with bill shorter than head, with 

 nasal fossa distinctly defined, the nostrils narrowly elliptical, wholly 

 pervious and parallel with the maxillary tomium. 



Figure 10. — LaUrallus jamaicensis. Natural size. 



Three subgenera in North and Middle America, which may be 

 described individually in detail as follows (ex Kidgway manuscript 

 in which they were considered of generic rank) : 



1. Subgenus Creciscus Cabanis. 



Bill much shorter than head (little if any more than half as long), 

 subcuneate in lateral profile, its depth at base equal to a little more 

 than one-third the length of cuhnen, its width at same point equal to 

 about two-thirds the height; cuhnen elevated basally, slightly de- 

 pressed above anterior end of nostril, thence gently decurved and 

 slightly convex to the obtuse tip of maxilla ; gonys a little more than 

 half to about two-thirds as long as mandibular rami, nearly straight, 

 slightly ascending terminally; mandibular rami without distinct, if 

 any, lateral groove ; nasal f osa rather large sharply defined, extending 

 half way to tip of maxilla or a little more; nostril relatively large, 

 narrowly elliptical, wholly pervious, parallel with maxillary tomium, 

 its anterior end much nearer to edge of loral feathering than to tip of 

 maxilla ; anterior outline of loral feathering forming a vertical nearly 

 straight or slightly convex line; that of frontal feathering divided 

 medially by a very short and small obtusely angular indentation, 

 formed by base of cuhnen; malar antia about on line with anterior 

 outline of loral feathering, the mental antia on line with or slightly 



