54 6 PICARIAN BIRDS. 



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

 build an open nest and lay white or light-coloured eggs. Xo 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 agithognathous 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 GALBULTDJS. 



Commencing with the climbing section of t lie 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 die 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 (BrachygaJha 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. . . " 



constitute a subfamily group : GaUnda and the allied genus I rogawa 



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 (GalbvZa viridis) is the best known species of the family, and is 



