1864.] MR. W. K. PARKER ON THE KAGU. 71 
they have retained a certain embryological simplicity of structure, 
and are thus less typically ornithic than their relatives the Gulls, on 
one hand, and the Ibises, on the other. 
The typical Fowls and the typical Geese and Ducks appear to 
form two more groups of equal value with the Ralline and Pluvialine 
groups; but as these two simple types do not bear very directly upon 
the subject of this present paper, they will be considered on some 
other occasion. 
Any one who has mastered the development of a Rail or a Plover 
will be in a state of fitness to study the meaning of what he will see 
in the structure of the Heron and of the Crane. 
At present my view of the matter is, that, whilst the Heron has 
risen considerably higher in the bird-scale than the Crane, yet they 
are intimately related ; moreover, that the Heron has full two- 
thirds of the ralline nature in it to one of the pluvialine, and, on 
the other hand, that the Crane has in it twice as much of the 
Plover as of the Rail. 
In supposing these birds to be thus double in their nature, I do 
not forget that they have characters peculiar to themselves alone ; 
identity-characters they might be called: we see this everywhere in 
nature; and those of us who have large families know well that, 
whilst each child is in one sense a copy of both parents at once, yet 
he holds his own, and has so much and such well-marked indivi- 
dualism as to make him in a certain sense like the starting-point of 
divergence towards a distinct species. I here append a sort of scheme, 
showing some of the more important relationships of the Kagu, one 
of the best examples of a multiple type :— 
Rallus. Ardea. Grus. Pluvialis. 
4 Nycticoraz. An de Himantopus. 
Brachypteryz. Tigrisoma. Balearica. Gdicnemus. 
Rhinochetus. BLurypyga. Psophia. 
pant Dap nn 
The Rhinochetus, the Psophia, and the Eurypyga are on the same 
level ; they are intimately related inter se, and very closely also to the 
Cranes and Herons. Iam not aware whether, in placing them on 
the same line, I have truly indicated the ornzthic height of each. In 
the upper line it is certainly not so; yet that is a natural arrangement 
in one important matter ; for the Heron comes near to the Rail, and 
the Crane to the Plover, and all are intimately related. 
The Psophia is the truest Crane in the bottom line, yet its skull 
is principally ralline in character ; the Eurypyga comes nearest to the 
Heron: as for the Kagu, whether it be most of a Crane, a Night- 
Heron, or a Wingless Rail, I will not say; it has a more distant re- 
lationship with the Stone-Plover (dicnemus). 
