XXIU 



B. Eostro albo, 



genis albis, gul^ concoloribus 4. B. albigularis, p. 45. 



genis fuscis, pileo concoloribus 5. B. melanosterna, p. 47. 



It may be noted that in a large series of B. luguhris recently obtained in British Guiana by 

 Mr. Whitely, the sexes (as determined by the collector) are alike, both male and female having 

 a conspicuous white ventral patch. It is probable, therefore, that the specimen figured (PI. XI.} 

 and described (p. 40) as a female, with this patch rufescent, is immature, or even that the 

 Colombian form with the rufous belly may belong to a distinct species. 



Genus IV. JACAMARALCYON*. 



Type. 



Jacamaralcyon, Less. Tr. d'Orn. p. 235 (1831) J. tridactyla. 



Cauax, Cab. in Wiegm. Arch. 1847, i. p. 347 /. tridactyla. 



Fig. 4. 



Jacamaralcyon tridactyla. 



a. Bill, from side. b. Bill, from above, c. Wing-end, from inside, d. Tail-end, from below. 



e. Left foot, from inside. 



Char. Gen. Brachygalbce, sed cauda elongatiore, et digito primo omnino absente. 



The only known species of this genus is /. tridactyla, p. 49, 



* '■^Alcyon, Spix, 1824," is given by Gray and other writers as a synonym of this genus. But this term is not to be 

 found in Spix's 'Aves Brasilienses,' and ajipears to rest on a misquotation of Cuvier (Kogu. An. 1829, i. p. 448). 



