ESSENTIAL CHARACTERS OF THE ORDERS. 3 



epithelium soft and rugous, or very thin. Intestine short and 

 of moderate width, in a few species which feed on fish very 

 long and extremely slender ; coeca in the diurnal very small 

 or obsolete, in the nocturnal oblong and large. Feet strong, 

 with four toes, of which the outer is versatile in the nocturnal 

 species ; claws long, curved, tapering, very acute. Wings 

 always large, but varying in length. Tail of twelve feathers. 

 PL IV, V, XX, XXI. 



ORDER X. EXCURSORES. SNATCHERS. 



Bill short or of moderate length, very broad at the base, 

 compressed only at the tip ; upper mandible with rather wide 

 basal sinuses, filled by the nasal membrane, which is feathered, 

 the edges notched close to the decurved acute tip. Tongue 

 narrow, flat, thin-edged, with the point slit or lacerated. 

 OEsophagus wide, without crop ; proventriculus oblong ; sto- 

 mach elliptical or roundish, moderately muscular, with the 

 lateral muscles distinct, and the epithelium dense and rugous. 

 Intestine short and wide, with very small coeca. Feet of mo- 

 derate size or very small ; tarsus slender ; hind toe long and 

 stouter, lateral toes nearly equal, anterior moderately spread- 

 ing ; claws rather long, curved or arched, much compressed, 

 laterally grooved, very acute. Wings generally rather long, 

 more or less rounded, with the first quill very small. Tail of 

 twelve feathers. PI. XXII. 



ORDER XL VOLITATORES. GLIDERS. 



Bill very short in proportion to its breadth ; mouth extremely 

 wide ; upper mandible with the tip very small, and the nasal 

 sinuses feathered. Tongue short, flattened, sometimes very 

 small. (Esophagus wide, somewhat funnel-shaped, but with- 

 out crop ; proventriculus moderate. Stomach broadly ellipti- 

 cal, moderately compressed, in the diurnal species muscular, 

 with thin broadly rugous epithelium, in the nocturnal, very 



