IBIS. IBIS. 491 



longitudinal ridge ; upper mandible little concave, with 

 two or four prominent lines. Tongue extremely short, tri- 

 angular, flat, thin, broadly emarginate and papillate at the 

 base, its tip obtuse. (Esophagus wide, proventriculus mode- 

 rate ; stomach large, broadly elliptical ; its muscular coat 

 very thick, with the lateral and inferior muscles distinct and 

 strong ; the epithelium thick, dense, longitudinally rugous ; 

 intestine rather long, of moderate width ; cceca very small 

 and cylindrical ; cloaca globular. 



Nostrils linear or oblong, sub-basal, in the fore part of 

 the narrow bare nasal membrane. Eyes rather small. Aper- 

 ture of ear very small. Feet long and rather slender ; tibia 

 bare for a considerable space, and reticulated with hexagonal 

 scales ; tarsus rather long, reticulate in the larger species, 

 scutellate in the smaller, or partially reticulate and scutel- 

 late ; toes rather long, moderately stout ; the first more 

 slender, articulated on the same plane as the rest; the 

 second a little shorter than the third ; all scutellate in their 

 whole length, flattened beneath ; the anterior webbed at the 

 base. Claws short or moderate, slender, compressed, slightly 

 arched, acute, that of the middle toe with the inner edge 

 thin. 



In young birds the head is feathered, except the loral 

 spaces and the skin between the crura of the lower man- 

 dible ; but in old birds, one species excepted, more or less of 

 the head, sometimes the face and throat, sometimes the 

 whole head, and sometimes nearly the whole neck besides, 

 are denuded. Plumage moderate ; feathers of the head and 

 neck slender, on the other parts ovate and of moderate 

 length. Wings long or of moderate length, broad, of about 

 twenty-five quills ; primaries firm, broad, rounded, the outer 

 three somewhat sinuate on the inner web, the third gene- 

 rally longest, the second a little shorter, and not much 

 exceeding the first ; secondaries broad and rounded, some of 

 the inner about as long as the longest primary when the 

 wing is closed, or longer, decurved, with the filaments loose. 

 Tail short or moderate, even or rounded, of twelve broad, 

 rounded feathers. 



From Tantalus to Ibis the transition is evident, while 



