384 NATURAL III STORY OF BIRDS. 



iiisli lis with uiiriuostionaldc jiroof of all tlio details; l)iit, takin*: all the evidence into 

 considi-ralioii, ami wcitjliiiii; it i-aivfully, tliu follow iiiir si'fiiiN to In- in accordance with 

 facts: The smooth-hilled ani, which inhahits the West Indies, often Jmilds its own 

 separate nest, and rears its young sejiarately. Hut as often, or j)erhai)s oftener, several 

 females unite to huihl 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 aiul sticks, lined with leaves, large and dee]). 

 In many instances the eggs :n'e found in regular layers, with leaves and grass-straw 

 between, and it has been assumed that it was causeil 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 buildiTig the nest after the first ones have 

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

 present, and that the breeding habits of tlie anis is a very j)roniismg field for future 

 researches. De Saussure asserts that the anis "breed together in comjiany as well in 

 Mexico as in the Antilles," referring to the groove-billed sjiecies, ami, 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 (6'«iVa 

 f/Nint), 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 aid's 



To those only su])erficially acquaintiil wiili the external habits of the birds coni- 

 j)osing the super-family CORAt'IOIDK.K, viz., the oil-bird, tlie 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. Kegarding these, however, the 

 doubt is so great, indeed, that some recent systeinatists 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 regarding one single character as indicative of relation- 

 shi]>. In this case it is the jialatal 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 comitaratively little value in the present order, since we m.ny 

 find a desmognalhotis and schizognatlious arrangement within the same grouj) of birds, 

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

 palates are illustrated by the accomi)aiiying cuts of the arrangement in tiie oil-bird, 

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

 vomer is jxiinted anteriorly and lilomled with ]ialatiiies; the maxillo-))alatines are 

 united, and the skull, consequently, <lesmognathous; the j)alatines also meet across the 

 median line, presenting a very peculiar fe.itiire, each being folded upon itself behind 

 the junction, and lateral posterior ]n'ocesses are .ibsent; basi])terygoid facets are 

 ]>resent. The podargi have a very different palate (Fig. IStJC), the pal.atines being 

 very broad with large lateral posterior processes and only i-udiments of basipterygoid 

 facets. Finally, the goat-suckers ])roi)er (Fig. ISGB) are distinguished by a palatinal 

 arrangement nearly typical j)asserine, consequently schizognathous, with the vomer 

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

 small basi|)terygoid ])rocesses 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 



