Mr. P. L. Sclater on the Spur-winged Geese. 71 



Dr. Giinther has called my attention to the fact, that the orifices 

 which commonly occur in the skulls of Graltce and Anatidce, situate 

 in the occipital bone on both sides of the foramen magnum, are re- 

 markably small in both these birds, particularly so in P. Ruppellii. 



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. Ruppellii, and 

 the bones are likewise thicker and stronger : — 



P. gambensis. P. Ruppellii. . 



Length of humerus 7*4 7'6 



of ulna 6'5 6*9 



of radius . . 6*25 6'6 



of metacarpus 3*8 4*0 



Comparing the posterior extremities, we find the tarsi and toes, 

 again, longer in P. Ruppellii, as the following dimensions prove : — 



P. gambensis. P. Ruppellii. 



Length of femur . . . . : 3*9 4*0 



of tibia 6-8 7*1 



of tarsus 4*5 4*6 



of middle toe from base of 



tarsus to the end of the nail .... 4 # 4-5 4' 6 



The pelvis is rather narrower in P. Rilppellii, the distance between 

 the trochanters measuring 1*9 in. ; in P. gambensis 2*1 in. 



The vertebrae are, cervical 15, dorsal 10, sacral 13, caudal 8 ; total 

 40 ; the true ribs 8, the false 2, in both species. 



The tracheae of these two birds, though, as might have been ex- 

 Fig. 1. Fig. 2. 



