PILHERODIUS.—TIGRISOMA. 177 
Pure albus, dorso alisque clare griseo lavatis; pileo cristato nigro, plumis nuchalibus albis ornamentalibus 
valde productis ; fronte cinerea ; facie laterali, collo undique, et corpore subtus toto lactescenti-albis ; loris 
et regione oculari nudis et rostro pulchre cyaneis, hujus apice viridescente ; pedibus plumbescenti-cinereis ; 
iride viridescenti-cinerea. Long. tota circa 23:0, ale 10-9, caude 3°75, culm. 3:4, tarsi 3-4. (Descer. 
maris adulti ex Rio de Janeiro. Mus. Brit.) 
© mari similis, sed noteo albo haud griseo adumbrato; plumis nuchalibus brevioribus. Long. tota circa 22:0, 
ale 10-2. (Descr. femine adulte ex British Guiana. Mus. Brit.) 
Hab. Panama (M‘Leannan*).—Sovutn America, from Guiana to Amazonia and Brazil 67. 
Though rare in collections, P. pileatus has a wide distribution in South America, 
and would appear to be by no means uncommon in Brazil and on the savanas of 
Guiana. According to Prince Maximilian of Neuwied, this Heron is only found in 
Brazil in the streams of the larger forests, where it is met with singly and appears to 
be very shy. During the nesting-time the birds are found in pairs on the banks 
of streams and brooks in the woods, especially on the stony shores or sand-bank 
where rocks and waterfalls occur. ‘They have been observed perching on high trees, 
in which they also nest. The food and habits are otherwise like those of the ordinary 
European species. 
The eggs do not appear to have been described. 
TIGRISOMA. 
Tigrisoma, Swains. Zool. Journ. iil. p. 362 (1828); Ridgw. Bull. U. 8. Geol. & Geogr. Surv. iv. 
p. 224 (1878) ; Sharpe, Cat. Birds Brit. Mus. xxvi. p. 193 (1898). 
Heterocnus, Sharpe, Bull. Brit. Orn. Club, v. p. xiv (1895); Cat. Birds Brit. Mus. xxvi. 
pp. 198, 281. 
The American ‘Tiger-Bitterns belong, according to Dr. Bowdler Sharpe, to the same 
section of the Ardeidz as the Night-Herons, but they differ from the latter in having 
the mandibles serrated and the subterminal notch nearly obsolete. The throat is 
entirely bare or only feathered in the centre, the sides being naked. 
Mr. Ridgway points out that in the genus Zigrisoma the pectoral and inguinal 
powder-down tracts are united into a continuous strip, and adds the following 
characters :—“ Tarsus with hexagonal scutelle in front. Outer toe longer than inner ; 
claws short, strongly curved. Plumage much variegated ; feathers of neck loose and 
fluffy.” 
Seven species of Zigrisoma are recognized, all of them being inhabitants of the 
Neotropical Region. Three occur within our limits, one species alone, 7. cabanisi, 
being met with in Mexico, but not in any part of the Southern United States. 
This bird differs from the other members of the genus in having the entire throat 
bare, and on this account it has been separated by Dr. Bowdler Sharpe under a 
distinct genus, Heterocnus. 
Very little has been recorded of the habits of these Tiger-Bitterns. 7" salmoni, of 
BIOL. CENTR.-AMER., Aves, Vol. III., October 1901. 23 
