TETRAONIDiE.] OSTEOLOGIA AVIUM, [P T EROCLINiE. 



Order IX. BASQUES. 



FAM. 1. TETEAOIIBJE. 



Subfam. Pteroclin^e. 



Pterocles, Temm. 



Arenarius, Pall. 



Cranium. Vertex, and occiput rounded regularly, and not projecting, as in the 

 pigeons; occipital ridge and protuberance not large, but distinct. Palatine bones 

 consisting of a narrow strip forwards, and slightly expanded posteriorly near their 

 junction with the interarticular bones; interarticular bones joining the sphenoid, as in 

 the pigeons. 



Sternum large in young birds, with two large fissures on the hinder margin, which 

 are obliterated in old birds. I have an old specimen with only a very small foramen 

 on one side ; keel very deep, anterior edge much scolloped out, and channelled for 

 the upper half; the strip of bone bounding the anterior fissure expanded at its tip 

 in a downward direction. 



Pelvis broad behind the acetabulum ; the divisions of the vertebrae well marked on 

 the upper surface, a large foramen on each side caused by the transverse vertebral 

 processes not being prolonged so as to anchylose with the ilium; this foramen is in both 

 young and old specimens, and is also to be seen in P. alchata. Ischium with a pro- 

 jection near the posterior edge, and above the ischiadic foramen. 



Ribs of moderate strength, the styliform process very broad for its proximal half, 

 turning upwards and pointed at its extremity. 



Furculum very small and very short, not reaching to above one-third of the distance 

 from the coracoids to the point of the sternum, with a very slight process at the 

 junction of the rami transversely flattened for its lower half, then twisted on its axis 

 and flattened longitudinally, and slightly expanded at its junction with the coracoids. 



Coracoids very short, extending slightly beyond the edge of the sternum, with a 

 slight spinous process on the inner edge a little above their articulation with the 

 sternum. 



Scapula regularly and much arched for two-thirds of its distal extremity, and 

 rounded at the tip. 



Wing-bones short ; humerus much shorter than the ulna, with a process similar to 

 that in the Columbidce on its upper proximal margin. 



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