158 SHOULDER-GIRDLE AND BREAST-BONE. 



/ 



Family" OTIN^E." 



Example. Otis tar da, Linn. 



The Bustards are gigantic Plovers, with massive bodies that suggest relationship with the 

 large Gallinse; this, however, is isomorphic and illusory. Like the (Edicnemus, they have the 

 " anterior pterygoid processes," which exist in nearly all the simple Pluvialinze, aborted ; and 

 this arrest of fundamental parts is combined in the Bustard with a modification of the furcnla 

 which carries them equally away from the Plovers and the Fowls, for the interclavicle is absent or 

 reduced to an unappreciable rudiment, whilst the rami have scarcely any trace (as in (Edicnemus) 

 of the upper pre-coracoid rudiment. These united clavicles, moreover, which are becoming 

 broader in the Thick-knee ((Edicnemus), are very straight and broad in the Bustard, and the 

 whole bone is much like that of the Palamedea, save that in the latter Bird the rami are of 

 unusual thickness. Another character by which the Otinse recede from both Fowls and 

 Plovers is the abortion of the sternal rostrum ; the keel, moreover, retires, as in the Turkey, and 

 is not very deep ; its four notches and its five xiphoid processes are typically Pluvialine. The 

 large wings and the perfectly distinct dorsal vertebrae, besides many other characters that could 

 be mentioned, all go to show that these Birds are merely huge terrestrial Plovers one culminat- 

 ing branch of the genealogical tree of that family ; not ready to grow into another Land-type, but 

 having, perhaps, in some remote age, one common ancestry with the Gallinaceous Ground-birds. 



Family' 1 



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Sttb-fam. 1. " GROINS proper." 



Examples. Grus montignesia, Bonap. ; Grus antigone, Linn. ; Balearica pavonina, Briss. 



Sub-fam. 2. " PSOPHIIN^." 



Examples. Psophia crepitans, Linn. ; EJtinochelus jubatus, Verr. et Des Murs. ; Eurypyga 

 helias, Linn. 



The genera Grus, Anthropo'ides, and Balearica, form a very natural group, and easy of 

 definition ; but the three genera which I have placed together as the Sub-family Psophiinae 

 differ in no small degree from the more familiar typical Cranes, and in a less, but considerable 

 degree from each other. The reason appears to be this, that the Psophia and the Eurypyga in 

 tropical America, and the Kagu (Rhinochetus) in Australia, each represent a nearly extinct group ; 

 and the three groups may in past times have rivalled the typical Sub-family in genera and 

 species. As these scantly represented types bear a fundamental embryonic relation to the nobler 

 typical species, a comparison of the structures of the embryo of the latter will correspond with 

 and explain the feebly expressed adult condition of the former ; whilst, on the other hand, we 

 shall be able to see in the variations from what is typically Gruine in the aberrant forms, to what 

 outlying groups the Cranes have most affinity. I am able to give (see Plate XIV, figs. 6 8, 



