EUMOMOTA.—PRIONORNIS. 467 
the tail, while they were in the well—catching hold of it and drawing it round, first on 
one side, then upon the other, always using the point and not the whole of the bill. 
_ “On examining the bill, it is found to be dentated at the middle portion and smooth 
at the tip and base. The smooth portion at the tip of the upper mandible fits very 
closely with the lower one, something after the fashion of scissors, and the bill therefore 
is well adapted to the work of feather-trimming. 
‘On closer inspection of the shaft, we find that traces of a web still remain, showing 
that it did not come so by a natural growth; so that after a careful examination of 
the structure of the bill, and considering the unevenness of the shaft where the webs 
are missing, as well as the time of disappearance of the latter, we must conclude that 
what nature does not do by narrowing the feather, the bird by its natural instinct of 
beauty and symmetry does by its bill.” 
Dr. Gaumer further states 1! that he has seen as many as a hundred birds issue from 
a single well or “ senote.” 
PRIONORNIS. 
Crypticus, Swainson, Classif. Birds, ii. p. 338 (1837) (nec Latreille). 
Prionirhynchus, Sclater, P. Z. 8. 1857, p. 256 (nec Jacquin and Lucas, 1854) ; Sharpe, Cat. Birds 
Brit. Mus. xvii. p. 315. 
In some respects this genus is the most definite of the Momotide ; its wide, flattened, 
curved bill with its distinct ridge along the culmen, which is even hollowed out for 
the greater part of its length, is not like the bill of the members of any of the other 
genera. On each side of the culmen the bill is concave instead of convex, as in all 
the others, and the serrations of the maxilla and mandible are exceedingly fine and 
numerous. ‘The tarsi are considerably shorter in proportion to the wings than in the 
rest of the family, and the feet relatively smaller. The antrorse loral feathers are short, 
not reaching nearly to the line of the round nostrils. The tail consists of ten feathers, 
which are graduated much as in Momotus. 
Two species of Prionornis are known, both of them occurring within our limits; 
of these, P. platyrhynchus has a wide range in the Valley of the Upper Amazons, is 
found in the State of Panama, and as far north as Nicaragua. ‘The other species, 
P. carinatus, is restricted to Eastern Central America, from. British Honduras to 
Nicaragua, and has also been recorded from Costa Rica. 
Mr. Sclater’s name Prionirhynchus being unfortunately preoccupied in Crustacea, he 
suggests Prionornis as a substitute for it. 
1. Prionornis platyrhynchus. 
Momotus platyrhynchus, Leadbeater, Trans. Linn. Soc. xvi. p. 92’; Jard. & Selb. Ill. Orn. iii. 
t. 106°. 
Crypticus platyrhynchus, Swains. Classif. Birds, ii. p. 338°; Cassin, Pr. Ac. Phil. 1860, p. 136%; 
Lawr. Ann. Lyc. N. Y. vii. p. 290°. 
. 59* 
