40 
sides, so that the space enclosed is nearly a quadrant. In P. gam- 
bensis the corresponding outline is carried back much further towards 
the protuberance, and formed of two lines, which terminate in a cen- 
tral angle, so that the space enclosed is nearly a rhombus. 
Dr. Giinther has called my attention to the fact, that the orifices 
which commonly occur in the skulls of Gralle and Anatide, situate 
in the occipital bone on both sides of the foramen magnum, are re- 
markably small in both these birds, particularly so in P. riippellit. 
The sterna of the two birds, as far as the comparison can be made 
(that of P. gambensis being rather distorted by disease), do not pre- 
sent any material points for comparison. The foramina, which in 
both species are closed at the base, are rather longer and larger in 
P. gambensis. 
The subjoined measurements in inches of the bones of the wings 
show that these organs are comparatively longer in P. riippellii, and 
the bones are likewise thicker and stronger :— 
P. gambensis. P. riippellit. 
Length of humerus..............  7°4 7°6 
he ee ore 6°5 6°9 
GUM «a cu nia se gees 6°25 6°6 
—of metacarpus ............ 3°8 4°0 
Comparing the posterior extremities, we find the tarsi and toes 
again longer in P, riippellii, as the following dimensions prove :-— 
P. gambensis. P. riippellit. 
Length of fenmiri is .teee Ses. 3°9 40 
Otitthinwie so cotk a ctotee... 68 FA 
OUMPAEIUS 2. ER. oe oe 4°5 4°6 
— of middle toe from base of 
tarsus to the end of the nail .... 4°45 4°6 
The pelvis is rather narrower in P. riippellii, the distance between 
the trochanters measuring 1°9 in. ; in P. gambensis 2°1 in. 
The vertebre are, cervical 15, dorsal 10, sacral 13, caudal 8 ; total 
40 ; the true ribs 8, the false 2, in both species. 
The tracheze of these two birds, though, as might have been ex- 
pected, showing a general resemblance, present the following differ- 
ences, which are greater than such as are usually found in indivi- 
duals of the same species. 
When dried, they are of nearly the same length, viz. about 14-5 in., 
but the bronchial rings are 151 in number in P. riippellii, and only — 
138 in P. gambensis. The tubes are flattened throughout the 
greater part, becoming cylindrical at 1°5 inch from the lower extre- 
mity. Here they are much compressed, and develope a large osseous 
bulb on the left side. The lower portion only of this bulb, as 
usual, is completely ossified, the upper part being covered with fine 
framework, which, as will be seen from the accompanying woodcut, 
assumes a different pattern in the two species. In P. riippellii (figs. 2 
and 4) the bulb is wider, higher, and much compressed ; in P. gam- 
bensis (figs. 1 and 3) shorter and comparatively much thicker. This 
is particularly observable in the side view, as shown in figs. 3 and 4, 
i 
