384 NATURAL HISTORY OF BIRDS. 



nish us with unquestionable proof of all the details; but, taking all the evidence into 

 consideration, and weighing it carefully, the following seems to be in accordance with 

 facts : The smooth-billed ani, which inhabits the West Indies, often builds its own 

 separate nest, and rears its young separately. But as often, or perhaps oftener, several 

 females unite to build but one nest. In this they all deposit their eggs, which they 

 incubate in common, rearing the young ones together when hatched. Often as many 

 as twenty eggs blue, with a white chalky covering are found in one nest, which 

 is said to be a rude collection of twigs and sticks, lined with leaves, large and deep. 

 In many instances the eggs are found in regular layers, with leaves and grass-straw 

 between, and it has been assumed that it was caused by the females covering the eggs 

 while leaving the nest, to preserve them at an equal temperature. It may be, how- 

 ever, that subsequent females continue building the nest after the first ones have 

 deposited the eggs, though it must be conceded that we know nothing definitely at 

 present, and that the breeding habits of the anis is a veiy promising field for future 

 researches. De Saussure assei'ts that the anis " breed together in company as well in 

 Mexico as in the Antilles," referring to the groove-billed species, and, according to 

 Azara, the South American species, C. major, has a similar habit, at least in Para- 

 guay. It is very suggestive in regard to the relationship of the piririgua (Gruira 

 guira), that the last mentioned author attributes to it the same communistic breeding 

 habits, and that its eggs are covered with a chalky layer similar to that of the ani's 

 eggs. 



To those only superficially acquainted with the external habits of the birds com- 

 posing the super-family CORACIOIDEJE, viz., the oil-bird, the podargus, the true goat- 

 suckers, the rollers, and the kirumbo, the statement will be received with some surprise 

 that there has been less doubt in regard to the affinity of the last-named three types, 

 than to whether the first two really belong here. Regarding these, however, the 

 doubt is so great, indeed, that some recent systematists not only make the oil-bird a 

 separate order by itself, but place the podargi and goat-suckers in two different orders. 

 This is chiefly the result of regai-ding one single character as indicative of relation- 

 ship. In this case it is the palatal arrangement and the form of the palatine bones 

 which have resulted in the separation of these forms, but it would almost seem as if 

 these characters have comparatively little value in the present order, since we may 

 find a desmognathous and schizognathous arrangement within the same group of birds, 

 the intimate relationship of which cannot be doubted in the least. The different 

 palates are illustrated by the accompanying cuts of the arrangement in the oil-bird, 

 the podargus, and the goat-sucker. In the first-mentioned type (Fig. 186 A), the 

 vomer is pointed anteriorly and blended with palatines; the maxillo-palatines are 

 united, and the skull, consequently, desmognathous ; the palatines also meet across the 

 median line, presenting a very peculiar feature, each being folded upon itself behind 

 the junction, and lateral posterior processes are absent; basipterygoid facets are 

 present. The podargi have a very different palate (Fig. I860), the palatines being 

 very broad with large lateral posterior processes and only rudiments of basipterygoid 

 facets. Finally, the goat-suckers proper (Fig. 186B) are distinguished by a palatinal 

 arrangement nearly typical passerine, consequently schizognathous, with the vomer 

 truncated anteriorly, but the slender palatines are enormously expanded behind, and 

 small basipterygoid processes are present. Parker calls them * incessorial schizognaths.' 



Notwithstanding these important differences in the basis of the skull, we regard 

 these three types as related. Indeed, were it not for the palate we should not think 



