546 PICARIAN BIRDS. 



white eggs in an open nest, while humming-birds, which are also Picarian, likewise 

 build an open nest and lay white or light-coloured eggs. No definite rule can be 

 laid down as to the nesting of the Picarians, and there are further exceptions, 

 though of a modified kind, and capable of a different explanation, such as occur 

 in the case of the cuckoos, some of which lay white eggs, and others variegated 

 and coloured ones. Although, in addition to the above not very important 

 features, there are certain osteological characters peculiar to the Picarians, 

 such as the form of the upper arm-bone or humerus, which exhibits well-marked 

 differences from the corresponding bone of the perching birds, the definition 

 of the order by means of well-marked and exclusive features is by no means easy. 

 The palate is sometimes of the so-called segithognathous type, and at others of 

 the bridged or desmognathous form ; while the structure of the foot is variable 

 in every degree, some Picarians having a foot in which the fourth toe is directed 

 backwards, while in others the foot has the front toes joined together, so as to form 

 a very flat perching surface. The Picarians may be divided into three chief 

 sections, which may be called Scansores, or climbing Picarians ; Coccyges, or cuckoo- 

 like Picarians; and Coraciiformes, or roller-like Picarians: the chief differences 

 between these groups occurring in the arrangement of the tendons of the feet, which 

 need not be explained in a work of the present nature. 



THE JACAMARS. 

 Family GALBULID^:. 



Commencing with the climbing section of the order, our first representatives 

 are the South American jacamars, of which about twenty species are known. All 

 these birds have the so-called zygodactyle type of foot, in which the fourth toe is 

 directed backwards parallel to the first. The bill is peculiarly long and straight ; 

 there is an aftershaft to the body-feathers, which does not occur in the allied group 

 of the puff-birds ; and there are some further differences in the arrangement of the 

 feathers of the under surface, the tract on the breast having a branch on the throat. 

 The number of tail-feathers varies in a somewhat peculiar manner, the normal 

 number being twelve, but in two genera out of the six (Brachygalba and Jaca- 

 maralcyon) the outer feather on each side is wanting, thus reducing the number 

 of feathers to ten. Although nothing absolutely decisive is known as to the 

 breeding-habits of the jacamars, it is stated that in Tobago they build in holes in 

 mud-banks, like the motmots, and lay pure white and nearly spherical eggs ; while 

 the three-toed Brazilian jacamar has been seen boring holes in banks as if for the 

 purpose of nesting. 



Together with four other genera of the family, the true jacamars 

 True Jacamars. . J ,777 T ,, n- i 7- 77 



constitute a subramily group ; (jrcUouia and the allied genus UrogaLoa 



having the middle pair of tail-feathers elongated, while in the others the tail is 

 short and squared ; the three-toed jacamars (Brachygalba) being notable for the 

 feature from which they take their name. In these jacamars the prevailing colour 

 of the plumage of the upper-parts is in most cases bronzy or metallic green. The 

 green jacamar (Galbida viridis) is the best known species of the family, and is 



