514 ME. W. K. PARKEE ON THE OSTEOLOGY OF THE KAGU. 



bone is rounded. The coracoid (PI. XCT. fig. .3, a; and PI. XCII. fig. 6, mcr) is an 

 nnusually long and feeble bone; its head is hooked and tuberculate, and its meso- 

 coracoid process (mcr) is square ; this process, as in the Eurypyga, is continuous with a 

 sharp keel that runs along the inner side of the bone, and becomes considerably 

 de\eloped at the angle below. At the outer angle below, the epicoracoid hook [ea') 

 is nearly obsolete. The coracoids (Pi. 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 Ewrypyga the bone is stouter, more V-shaped, and has a distinct inter- 

 cla'^icular process ; in the Kagu this part is much aborted. The whole outline is 

 that of three-fourths of a very elegant ellipse (PI. XCII. fig. 6, //•) ; and the bone is 

 widest below and above ; the upper outcurved parts are broad and flat ; and there is a 

 very evident enlargement fi-om 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-gii-dle and 

 Sternum,' Eay 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 tyj^ical Crane 

 {op. cit. pi. 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 

 PI. XCII. fig. 6, where the sternum appears too short by half an inch) ; the lateral views 

 (PI. 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 Rallidse, but further backwards it narrows-in still more, and then dilates 

 somewhat at the xiphoid end (PI. XCII. fig. 6, x) : this part is only slightly trifid. The 

 general feebleness of the Kagu's sternum will be well seen by comparing it (PI. XCT. 

 figs. I & 3, and PL XCII. fig. 6) with that of the entirely unossified sternum of the 

 newly hatched Mantchouri Crane (see 'Shoulder-girdle and Sternum,' pi. 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 (PI. XCI. fig. 3, c.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 



