100 The Philippine Journal of Science 1919 
ribs, are without appendages. Only the first pair of these pelvic 
ribs has costal ribs, while an aborted floating hzmapophysis, 
long and slender, completes the series. 
Morphologically, the grebe’s pelvis is well known—compar- 
atively speaking as well as actually; it is shorter in Tachybaptus 
than in either Colymbus or Podilymbus; in the latter genus it 
is extremely long and strikingly narrow. Nothing of particular 
note marks the small caudal vertebre in this little grebe of the 
Philippines. 
In regard to its shoulder girdle, or pectoral arch, it comes 
nearer Podilymbus than it does to Colymbus, especially in the 
matter of the U-shaped furcula; for there is no hypocleidium 
present except in the case of Colymbus cornutus, where it is a 
well-developed peg of bone directed backward. 
The sternum presents all the usual characters as we find 
them in the grebes generally; it is nonpneumatic, and the mid- 
xiphoidal notch is notably shallower than in the dabehick and 
most other American grebes. This is also true of the lateral 
sternal notches, while the lateral xiphoidal processes are stouter 
and shorter than we find them among the birds last mentioned. 
As among the Colymbide generally, the long bones of the 
arm and hand in Tachybaptus are completely nonpneumatic, 
while in form they are long and slender. While the usual 
“sigmoid curve” is to be seen in the humerus, it is not nearly 
as well marked as we find it in many other groups of birds. 
Then, too, the general characters of the proximal extremity of 
the bone are more or less feebly developed—a fact that causes 
no‘surprise, in as much as these birds are feeble fliers as com- 
pared with many other aquatic species. There are no claws 
on the phalangeal joints, and the carpometacarpus is long and 
slender. 
Judging from appearances in the prepared skeleton, it would 
seem that the femur and the superior halves of the bones of the 
leg might be to some extent pneumatic, which is not the case in 
the grebes found in North America. Otherwise, the morpho- 
logy of this part of the skeleton in Tachybaptus is entirely in 
agreement with that of any small grebe; this especially applies 
to the patella and other features of the knee joint. As in other 
grebes the inner trochlea of the tarsometatarsus is situated pos- 
teriorly on the shaft of the bone, and the accessory metatarsal, 
with its joint and claw (hallux), is found well up the shaft 
above it. The ungual joint of the midanterior toe is much 
expanded and shell-like, while in the case of those of the other 
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