6 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 
s of the Jacanide are 
The osteological and other internal character L 
Additional (external) 
the same as those given for the Jacani on p. 5. 
characters are as follows: ; 
Bill moderate in size, about as long as head, straight, compressed, 
the rhinotheca usually developed basally into a more or less con- 
spicuous frontal plate or “leaf,” sometimes a rictal lobe or leaf also; 
a more or less distinct metacarpal spur, in some genera conspicuously 
developed, conical, more or less recurved, and sharp, in others small 
and blunt; toes, including hallux, excessively elongated, with their 
claws long, slender, straight, and acute, that of the hallux much 
longer than its digit (sometimes three times as long) and slightly 
recurved. 
In general appearance, as well as in habits, the Jacanide resemble 
members of the Rallide more than they do the Charadrii, to which 
they are far more closely related, since, like the latter, they differ 
from the former in their schizorhinal instead of holorhinal nares, the 
presence of well-developed basipterygoid processes, absence of occipi- 
tal foramina and supraorbital grooves, emarginate instead of acumi- 
nate apex to’ vomer, and other characters. In the metacarpal spur 
they resemble certain genera of Charadrii, some of which also possess 
a rictal lobe.. In the character of their excessively elongated toes 
and claws, however, they are entirely peculiar. These enable them 
to walk.and run with ease upon the surface of floating leaves of 
aquatic plants. 
The Jacanide are of intertropical distribution, but America pos- 
sesses only one of the six recognized genera, the remainder being 
confined to Africa (including Madagascar), India, southern China, 
Borneo, the Philippines, New Guinea, Australia, etc. 
KEY TO THE GENERA OF JACANIDA. 
a. Head without frontal shield or lobes. 
b. Middle rectrices greatly elongated; tips of some of the primaries attenuated. 
(India to southern China, Philippines, Java, etc.). 
Hydrophasianus (extralimital).¢ 
bb. Middle rectrices not elongated; tips of primaries normal. (Southeastern Africa.) 
Microparra (extralimital).) 
aa, Head with a frontal shield. 
b. Frontal shield without free margins. (Africa, including Madagascar.) 
. Actophilus (extralimital).¢ 
a Hydrophasianus Wagler, Isis, 1832, 270 (type, by original designation, Parra sinen- 
sis Gmelin=Tringa chirurgus Scopoli).— Hydro phasis (emendation). 
> Microparra Cabanis, Journ. fiir Orn., 1877, 349 (type, by original designation, 
Parra capensis Smith).—Aphalus Elliot, Auk, v, July, 1888, 292 (type, by original 
designation, Parra capensis Smith). (Monotypic.) 
This form not seen by me. 
¢ Phyllopezus (not of Peters, 1877) Sharpe, Cat. Birds Brit. Mus., xxiv, 1896, 76 
(type, Parra africana Gmelin).—Actophilus Oberholser, Proc. Ac. Nat. Sci. Phila , 
June 2, 1899, 202 (new name for Phyllopezus Sharpe, preoccupied). (Two species.) 
