No. 3-] THE OSTEOLOGY OF THE PIGEONS. 497 



vertebrae fuse together to form one bone, and it has shortish 

 lamelliform hypapophyses beneath its center. All its ribs con- 

 nect in the usual manner by haemapophyses with the sternum, 

 as do the next succeeding pair which come from the fourth and 

 which is at the same time the only free dorsal vertebra. These 

 dorso-vertebral ribs have coossified unciform processes that are 

 rather broad and flat, and the last one may be fenestrated. A 

 pair of ribs come also down from the first sacral vertebra, but 

 they do not support epipleural appendages, nor do their haema- 

 pophyses quite reach the costal borders of the sternum. In 

 the specimen at hand there is also to be found a very small 

 pair of true "floating ribs"; they are immediately behind the 

 articulation of the sacral-vertebral rib and its haemapophyses, 

 one upon either side. 



Regarded as a whole, the pelvis of Ectopistes is seen to be 

 broad and comparatively shallow, and although the ilia are in 

 contact with the sacrum for their entire lengths, the union is a 

 very feeble one, ordinary maceration being often sufficient to 

 detach the ossa innominata. The sacrum is broad, roughly 

 lozenge-shaped, with a low "crista" anteriorly, and the inter- 

 diapophysial foramina very small, being confined to a single 

 row upon either side of the middle line. Concaved in front 

 for their pre-acetabular parts, the ilia are widely separated in 

 that region, while their posterior margins lie roughly in the 

 same curve with the line of the last sacral (or uro-sacral) 

 vertebra. 



Viewed laterally, we are to note the triangular notch on the 

 hinder pelvic margin, indicating the division between the ilium 

 and ischium. The post-pubic element is long and narrow, of 

 nearly uniform caliber, and projects considerably behind. 

 Distally the " foot " of the ischium rests upon it, and the obt2i- 

 rator space or cleft above is a long, narrow vacuity, which 

 in front opens into the small oval obturator foramen. There 

 is no evidence whatever of the presence of a pre-pubis. The 

 ischiac foramen and the acetabulum with its anti-trochanter are 

 also both small, and indeed this group of openings on the side 

 of the pelvis are comparatively closely huddled together and 

 of little size. Upon ventral aspect, we find in front the pair 



