Chap. V. 



OSTEOLOGIGAL DIFFERENCES. 



165 



bones. In the rock-pigeon, and in several domestic breeds, the edges of 

 the lower jaw on each side come close up to the premaxillary bones, so 



Fig. 26.— Skull of Runt, seen 

 from above, of natural size, 

 showing the reflexed margin 

 of the dittal portion of the 

 lower jaw. 



Fig. 27. — Lateral view of jaws, of natural size. 

 A. Rock-pigeon. B. Short-faced Tumbler. 

 C. Bagadotten Carrier. 



that no open space is left. The degree of down- 

 ward curvature of the distal half of the lower 

 jaw also differs to an extraordinary degree in 

 some breeds, as may be seen in the drawings 

 (fig. a) of the rock-pigeon, (b) of the short-faced 

 tumbler, and (c) of the Bagadotten carrier of 

 Neumeister. In some runts the symphysis of 

 the lower jaw is remarkably solid. No one would 

 readily have believed that jaws differing so greatly in the several above- 

 specified points could have belonged to the same species. 



Vertebrae. — All the breeds have twelve cervical vertebrse. 36 But in a 

 Bussorah carrier from India, the twelfth vertebra carried a small rib, a 

 quarter of an inch in length, with a perfect double articulation. 



The dorsal vertebra} are always eight. In the rock-pigeon all eight bear 

 ribs ; the eighth rib being very thin, and the seventh having no process. 

 In pouters all the ribs are extremely broad, and, in three out of four 

 skeletons examined by me, the eighth rib was twice or even thrice as broad 

 as in the rock-pigeon; and the seventh pair had distinct processes. In 

 many breeds there are only seven ribs, as in seven out of eight skeletons 

 of various tumblers, and in several skeletons of fantails, turbits, and 

 nuns. In all these breeds the seventh pair was very small, and was 

 destitute of processes, in which respect it differed from the same rib in 

 the rock-pigeon. In one tumbler, and in the Bussorah carrier, even 

 the sixth pair had no process. The hypapophysis of the second dorsal 

 vertebra varies much in development; being sometimes (as in several, but 



36 I am not sure that I have designated 

 the different kinds of vertebrae correctly: 

 but I observe that different anatomists 

 follow in this respect different rules, 



and, as I use the same terms in the com- 

 parison of all the skeletons, this, I hope, 

 will not signify. 



