1909.| ‘OF THE PASSERINE BIRD ARACHNOTHERA MAGNA. 53 
dorsal aspect; the pair of “notches” in the xiphoidal extremity 
giving rise to an outer xiphoidal process upon either side; the 
deep “keel” with its prominent carinal angle, anteriorly; and, 
finally, the fact that the bone is more or less pneumatic. The 
coracoids never decussate in their sternal beds, though in some 
species they almost appear to do so. Again, the hypocleidium of 
the furcula never comes in contact with the manubrial process of 
the sternum, though in some species the approach is extremely 
close (Hntomyza cyanotis). So much for the general characters, 
and Arachnothera has them all to perfection ; and there are a few 
minute pneumatic foramina in the middle line on the dorsal 
aspect of the bone, anteriorly, in this species. If we designate the 
length of the sternum by a line extending from the apex of the 
earinal angle of the keel to the mid-xiphoidal point posteriorly 
where the keel terminates, then this distance in A. magna 
measures 2°3 centimetres. This same measurement will be 
applied in the case of the sterna of the other species—as, for 
example, in Arachnothera longirostris, the length of the sternum 
is but 1°5 ems., and we find the body of the bone flatter, the 
xiphoidal notches comparatively deeper, the carinal a gle not so 
acute, and the keel of the manubrium conspicuous and vroduced 
well down upon the anterior border of the sternal cari. . The 
pneumatic foramina are scarce and in the same localit,. In 
Leptocoma grayi the sternum has a length of but 1:3 cms. 
In Cyanerpes cyanea, as representing the Coerebide, it measures 
1:7 ems., and here the bone is very thin and delicately constructed, 
with a small manubrium; deep notches and dilated extremities 
to the xiphoidal processes. These characters do not apply to the 
sternum of Cwreba chloropyga, another of the Cerebide, a species 
having the bone only 1:2 ems. long. 
Anthreptes malaccensis has a sternum which is the counterpart 
of that bone in A. magna, only it is much smaller, having a length 
of but 1:4 cms. 
Among the larger forms of the Meliphagidee we meet with 
characters in the sternum that are absolutely diagnostic, as, for 
example, there is no such a thing as mistaking the species had we 
but this bone to help us in such a bird as Acanthogenys rufigularis. 
Here, although it is of the usual passerine type, it is peculiar in 
having the anterior border of the sternal body very much 
thickened and rounded; this thickening is continued across the 
base of either costal process and up on to the mesio-posterior 
margin of the same. Such a thickening also defines the limits 
laterally of a deep mesio-longitudinal groove, deepest anteriorly, 
that 1s found upon the dorsal aspect of the body of the bone. 
For its anterior.moiety, thickly crowded together at the bottom 
of this groove, we find some thirty or forty pneumatic foraminal 
openings. Between the coracoidal grooves there is another 
single pneumatic foramen, and the external angles of the mid- 
xiphoidal prolongation are pronounced. The carinal angle is 
Proc, Zoou. Soc.—1909, No. XXXV. 35 
