CHIONIS MINOR. 107 



space, limited below by the pubis and above by the iscbima. It is con- 

 verted during life into an oval foramen by a stout ischio-pubic ligament. 

 The ramus of the ischium runs downward and backward as a long fal- 

 cate process, flat, thin, and curved on the flat somewhat inward. The 

 jmhis is long, very slender, shaped like an italic /, and crosses the is- 

 chium externally to its ramus, extending 0.40 beyond it, curving inward 

 as it passes backward. Both ischium and pubis extend considerably 

 beyond the coccyx posteriorly, and ajiproximate each other, inclosing, 

 with ilinm, an irregular, circular outlet, of which the sacro-pubic diam- 

 eter is 1.30 and the inter-ischiatic 1.10 inches. Internally the ilia are 

 deeply excavated opposite the sacrum for the kidneys, so that the 

 acetabular and ischiatic foramina pass out laterally from the cavity so 

 formed. Its roof is crossed by the sacral trabeculfe, and encroached 

 upon by the sacrum, somewhat like the ridge pole and lateral ties of the 

 roof of a house. This iliac cavity is limited anteriorly by the margin 

 of a ridge formed by the fusion of the ischium and pubes. Posteriorly, 

 although the rami of the ischium do not articulate or fuse together, 

 they touch, doubtless closing during life the whole obturator space, here 

 very long and narrow. 



¥ 



STATExMENT OF CONCLUSIONS DEDUCED FROM THE FOKE- 



GOING. 



HABITS, GENERAL APPEARANCE IN LIFE, AND EXTERNAL CHARACTERS. 



The observe!" is first struck by the strong resemblance which Chionis 

 bears to the pigeons, in general appearance, gait, and mode of flight. 

 The general shape of the body is of an ordinary columbine character, 

 the head being notably small, as usual in that group, the neck short 

 and full, and the body plump; the tail, moreover, having but 12 rectrices. 

 The sheath of the bill may furnish a distant analogy with the soft, 

 swollen membrane which covers the nostrils throughout the Columhcc. 

 But this is a mere resemblance, the affinity indicated being, as will be 

 seen later, with such sheaths as the ProcellarUdw and especially Lestri- 

 dince bear. The strongly convex outline of the frontal feathers at the 

 base of the upper mandible is a very decided columbine feature. These 

 superficial resemblances to Columbw are not correlated with more impor- 

 tant structural characters, and are themselves overbalanced by other 

 external features, which indicate relationship with other groups. Thus 

 the pterylosis is entirely difierent, large after-shafts and abundant down 



