520 MR. W. K. PARKER ON THE OSTEOLOGY OF THE KAGU. 
Porphyrio. The posterior sharp edges of the metatarsus seen in these birds have 
scarcely any existence in that of the Kagu. As in these its congeners, the Kagu has 
the outer lower condyle connected with the middle condyle by a bony bridge, so that 
the considerable open space between these two, below, is divided into a fenestra and a 
notch. ‘The condyles themselves (Pl. XCII. figs. 11 & 110) differ in the Kagu from 
those of its congeners; they are much more outspread (Reptilian) than in the Psophia, 
whilst in Hurypyga they are more compressed than even in Porphyrio, equalling what is 
seen in the Coot (Fulica atra), and approaching the condition of these parts in the 
Grebes (Podiceps). The small free metatarsal (Pl. XCI. fig. 1,7. m.t) is placed high 
up, as in the congeners of the Kagu ; and the “ hallux”’’ is of moderate length. The rest 
of the toes are slender, and rather long (Pl. XCI. fig. 1), the middle toe (d. 3) being more 
than an inch and a half shorter than the tarso-metatarse. In the Psophia the middle 
toe is only half the length of the shank; in Ewrypyga the middle toe is nearly two-thirds 
the length of the shank; whilst in Porphyrio it is a quarter of an inch longer than the 
tarso-metatarse. 
These variations are worth mentioning because of their zoological value; morpho- 
logically, however, they have much less import, as they relate mainly to the correlation 
of each type to its surroundings in actual life. 
In summing up the affinities of the Kagu, I may say that my view of it is that it is a 
generalized Crane, that it is nearer of kin to Eurypyga than to Psophia—the latter 
coming near to the Balearic Crane, whilst Hurypyga, like the Kagu, makes a very near 
approach to the Night-Herons amongst the typical Ardeine. The Kagu is related to the 
Rails ; but so, indeed, are all the Gruine ; and Professor Huxley has, with great sagacity, 
put both these families into one group, and has called this group the “ Geranomorphe ” 
(see Proc. Zool. Soc. 1867, p. 457). 
EXPLANATION OF PLATES XCI. anv XCII. 
PLATE XCI. 
Fig. 1. Side view of skeleton. 
Fig. 2. Upper view of cervical vertebre. 
Fig. 3. Side view of sternum and shoulder-girdle. 
* The hinder toe is evidently the true “hallux;” but in my former papers it was described as the second 
(d. 2), on the supposition that the spur of the Cock represented the innermost digit. 
