128 



NATURAL HISTORY OF BIRDS. 



We divide the family into several groups of lower rank, as true rails, wood-hens, 

 purple gallinules, true gallinules, and coots, the latter being distinguished by their 

 lobated toes, like grebes, the gallinules by the horny shield which covers the fore- 

 head. 



The true rails are distributed all over the world, being, however, chiefly tropical 



and especially numerous in America. They 

 are usually more or less sombre-colored birds 

 of very retired, partly crepuscular habits, 

 populating swamps and marshes, and very 

 little known except by their often loud 

 and harsh voice to others than those who 

 as sportsmen or naturalists make them a 

 specialty. The Virginia rail (Rallus virgiii- 

 ianus) and the Sora rail (Porzana Caro- 

 lina) are familiar examples from this conti- 

 nent, while the common European corn- 

 crake ( Crex crex) is only a casual visitor to 

 our eastern coast. 



Closely related to the rails proper, but 

 singularly specialized in many respects, are 

 the wood-hens, as they are called by the 

 English colonists in the South Sea. Several 

 species of the genus Ocydromus are inhabit- 

 ants of New Zealand, and have, like many 

 other bird types of the region, lost their 

 power of flight by disuse. They are rather 

 larsie birds, about the size of the domestic 



O ' 



fowl, with stout feet, small and weak wings, 

 and correspondingly feeble development of 

 the shoulder girdle and the breast-bone, the 

 keel being very low, as shown in the ac- 

 companying cut of the skeleton. The anal- 

 ogy of the retrograde development of the 

 fore limbs and the parts supporting them 

 in these birds, with the state of the struc- 

 ture in the struthious birds inhabiting the 

 same region, is very instructive as indicat- 

 ing the probable origin of the latter by a 

 similar process of reduction caused by disuse. 

 In this connection there is a point of con- 



FiG. 60. Skeleton of Ocydromus fuscus. 



siderable importance, viz., that in Ocydro- 



the angle between the scapula and the coracoids is less acute than in flying Cari- 

 nates, thus approaching the arrangement in the Struthionine bird, and in the equally 

 flightless extinct Hesperornis. A further hint in the same direction is the fact that the 

 angle mentioned is equally obtuse in the skeleton of the dodo. Some anatomists go even 

 so far as to suggest a comparatively close relationship between Ocydromus and the 

 kiwis, as, for instance, Prof. Garrod, Avho says " so many features have they in common, 

 that it would be difficult to bring convincing argument against the statement that Ocy- 



