514 MR. W. K. PARKER ON THE OSTEOLOGY OF THE KAGU. 
bone is rounded. The coracoid (Pl. XCI. fig. 5, cr, and Pl. XCII. fig. 6, mer) is an 
unusually long and feeble bone; its head is hooked and tuberculate, and its meso- 
coracoid process (mcr) is square; this process, as in the Ewrypyga, is continuous with a 
sharp keel that runs along the inner side of the bone, and becomes considerably 
developed at the angle below. At the outer angle below, the epicoracoid hook (ec7’) 
is nearly obsolete. The coracoids (Pl. XCII. fig. 6, cr) are separated below by the 
width of the anterior sternal notch; these bones are most slender just above the middle, 
where they are pinched to little above a line in thickness, whilst measured across the 
epicoracoid region they are five lines in breadth. The furcula (fr) is of a narrow 
U-shape; it is a much stronger bone than that of Brachypteryx or Ocydromus: in 
Psophia and Eurypyga the bone is stouter, more V-shaped, and has a distinct inter- 
clavicular process; in the Kagu this part is much aborted. The whole outline is 
that of three-fourths of a very elegant ellipse (Pl. XCII. fig. 6, fr); and the bone is 
widest below and above; the upper outcurved parts are broad and flat; and there is a 
very evident enlargement from the “ precoracoid segment” where it articulates at its 
side with the hooked head of the coracoid, and another addition at its tip where it joins 
the acromion (mesoscapula); this additional piece, which has become confluent with 
the clavicle on each side, is the ‘‘mesoscapular segment.” (See ‘Shoulder-girdle and 
Sternum,’ Ray Society, 1868, p. 179.) 
In relative size, general form, and in the degree of its morphological development, 
the sternum of the adult Kagu agrees with that of the ripe chick of a typical Crane 
(op. cit. pl. 14. p. 158). The curvature of the bone is so great that the lower view of 
the shoulder-girdle, when fairly seen, gives a foreshortened view of the sternum (see 
Pl. XCII. fig. 6, where the sternum appears too short by half an inch); the lateral views 
(Pl. XCI. figs. 1 & 3, st) show the elegant curvature that the xiphoid part of the 
sternum makes, passing both upwards and backwards to support the abdominal viscera. 
As in the Psophia and in the typical Cranes, the sternum of the Kagu is as narrow in 
front as in the Rallide, but further backwards it narrows-in still more, and then dilates 
somewhat at the xiphoid end (Pl. XCII. fig. 6, 7): this part is only slightly trifid. The 
general feebleness of the Kagu’s sternum will be well seen by comparing it (Pl. XCI. 
figs. 1 & 3, and Pl. XCII. fig. 6) with that of the entirely unossified sternum of the 
newly hatched Mantchouri Crane (see ‘Shoulder-girdle and Sternum,’ pl. 14. figs. 6-8). 
Even at that early stage the sternum of the typical Crane has a much larger keel (which 
articulates with the “furcula”), a definite “rostrum” in front overlapping “ coracoid 
grooves,” and has the normal Pluvialine fission of the xiphoid region of the sternum 
into middle, intermediate, and external xiphoid processes. 
The general curvature of the sternum is very similar in both these instances. The 
costal processes (Pl. XCI. fig. 5, ¢.p) are long, triangular, and are hooked inwards 
behind the posterior face of the coracoid, 
The two triangular flaps in which the sternal keel terminates in front in the embryo 
