512 ]Vni. W. K. PAEKEE ON THE OSTEOLOaY OF THE KAGU, 



The Eim/i^iyga is very typical in liaving a long neck, and very curiously isomorphic 

 of the Anhingas {Plot us) in the unusual elongation of this part' ; for whilst it has five 

 more joints in this region than the Green Bittern, it has the individual vertebrae as long 

 as in that true Ardeine bird. Yet this elongation of the cervical vertebrte, a most con- 

 stant character in the true Ardeinse, is not coupled with the swollen, spongy condition 

 seen in those birds, but the bones are quite Gruine in their histological characters. 



But the Kagu differs from all its congeners in the stoutness of its cervical vertebriE 

 (PI. XC'I. figs. 1, 2) ; this is a correlate of its very large ridgy head, and is similar to 

 what is seen in the Bal(enice]is. This incrassation of the cervical vertebrae is coupled 

 with a diminution of their number ; and the strength of the head and neck of this bird 

 is in curious contrast with the feeble condition of many other parts of the skeleton. 



In the cervical vertebrae, as in the rest of the skeleton, the Kagu shows a very much 

 feebler ossification (especially with relation to the fibrous bands that are attaclied to 

 tlie bones) than the Pso])hia and the typical Cranes ; in this it agrees with the Eurypyga ; 

 and the differeirce between the vertebrae of these two types is merely such as arises from 

 the slenderness of those of the Sun-Bittern and the breadth and shortness of those of 

 the Kagu. 



The "atlas" of the Kagu (PI. XCI. figs. 1 & 2, and PI. XCII. figs. 12 & 12 a) is a 

 strong ring of bone ; its upper portion projects on each side behind ; its centrum is tri- 

 dentate ; and it has the " cup" cut away in a rounded manner for the " odontoid process 

 of the axis." 



The ^' axis " (PI. XCI. fig. 1 and fig. 2, i3, and PI. XCII. figs. 13, 13 a, 13 h) has a thick 

 upper and a triangular lower spine ; over each of its oblique facets there is a thick ridge ; 

 and there is a small bony bridge on each side of the odontoid process (PI. XCII. figs. 13«, 

 Ub). 



The next vertebra (PI. XCII. figs. 14, 14 a, 14 1, 14 c) is intermediate in shape between 

 the " axis " and the cervicals of the hind region ; its spine is smaller than that of the 

 •' axis," it has a short, stout rib, confluent with the sides of the bone and forming a 

 bridge for the vertebral artery. The next ten vertebrae have scarcely any spine ; the 

 sixth approaches in character the typical form of those of the hind region (PI. XCI. 

 figs. 1 & 2, 15, and PI. XCII. figs. 15, 15 a, 15 b, 15 c). In this bone the transverse pro- 

 cesses project considerably; there is no process tending to wall-in the carotid artery 

 below ; the centrum is deeply conca^'e beneath, and is produced into two ears behind, 

 tlie transverse convexo-concave hinge being greatly produced outwards. The next four 

 have paired processes, tending to embrace the carotid arteiy ; the penultimate bone of 

 these (PI. XCI. figs. 1 & 2, 16, and PL XCII. figs. 16, 16 a, 16 b, 16 c) is seen to be of great 

 breadth, and rather short, with its oblique facets very diverging. In the next five joints, 

 instead of the paired " carotid processes," there is a flat inferior spine ; in these the 



' The abortion of the " ethmo-presphenoidal " band in the Sun-Bittern is in harmony with what we see not 

 only in the Stilt-Plover but also iu "the Cormorant. 



