54 6 PIC ARIA. \ BIRDS. 



white eggs in an open nest, while humming-bin Is, 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 hone 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 Hat perching surface. The Picarians may he divided into three chief 

 sections, which may he called Scansores, or climbing Picarians : ( Joccyges, or cuckoo- 

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



hit ween these -roups OCCUrring ill the arrangement Of the tendons of the feet, which 



need not hi- explained in a work of the present- nature. 



The Jacamars. 



Family G ALBV i.in.r.. 



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

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

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



directed h:ick wards parallel to the first. The hill is peculiarly long and straight : 

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



of the puff-birds ; and there me some further differences in the arrangemenl of the 



feathers of the under surface, the t ract on the hreast having a hranch 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- 

 maralcyori) 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 mot mots, and lay pure white and nearly spherical eggs; while 

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

 purpose of nesting. 



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



' constitute a subfamily group; Galbula and the allied genus Urogalba 



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 tin; 

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



