Parxer.—On Notornis mantelli. 251 
tule, however, a large coraco-scapular angle seems to be correlated with a 
Small carina sterni and large transverse sternal angle, and, taking birds of 
the same order, there is a tolerably close relation between these structural 
peculiarities and adaptation to a cursorial life. 
The table of comparative measurements given above shows* that, 
- arranged according to depth of carina sterni, or to size of transverse sternal 
a angle, the four genera of Rallide under consideration must be placed in the 
a following order :—1, Porphyrio, 2. Tribonyx, 8. Notornis, 4. Ocydromus. 
q Fig. 6 shows that the same order is maintained if they are arranged by 
a the coraco-scapular angle, which is least (86°) in Porphyrio, and greatest 
a (100°) in Ocydromus, and it will be seen that the list begins with a good 
a flier (Porphyrio), and ends with a bird of purely cursorial habits (Ocydromus), 
_ Similar series may be obtained by turning to other orders; in Anseres, for 
instance, we have 1. Anser, 2. Nesonetta, 8. Cnemiornis ; in Columbe, 1. 
a Columba, 2, Didus; and in Psittacine, 1. Ara, and 2. Stringops. In all cases 
_ loss of the power of flight is associated with the ratite characteristics of 
_ increase of transverse sternal and coraco-scapular angles, and decrease of 
‘carina, . 
There is still one other point to be observed i tion with the shoulder 
girdle: if the extremes of our ralline series be compared, i.e., Notornis or 
Ocydromus with Porphyrio, it will be found that the forward inclination of 
the coracoid from its sternal articulation is much less in the flightless forms 
than in Porphyrio, in other words, that the angle enclosed between the 
Coracoid and a fore-and-aft line drawn through the coraco-seapular articula- 
tion parallel to the long axis of the body is greater in Notornis and Ocydromus 
than in Porphyrio. Such an angle will, of course, vary according to the 
Position of the st i piration, so that it + size is of no import 
and it can only be of use in the comparison of extreme forms. 
The furcula of Notornis is slender and flattened from before backwards 
