Chap. V. 



OSTEOLOGICAL DIFFERENCES. 



175 



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 mnch in development ; being 

 sometimes (as in several, but not all Tumblers) nearly as prominent 

 as that of the third dorsal vertebra ; and the two hypapophyses 

 together tend to form an ossified arch. The development of the 

 arch, formed by the hypapophyses of the third and fourth dorsal 

 vertebrae, also varies considerably, as does the size of the hypapo- 

 physis of the fifth vertebra. 



The rock-pigeon has twelve sacral vertebra? ; but these vary in 

 number, relative size, and distinctness, in the different breeds. In 

 Pouters, with their elongated bodies, there are thirteen or even 

 fourteen, and, as we shall immediately see, an additional number 

 of caudal vertebras. In Eunts and Carriers there is generally the 

 proper number, namely twelve ; but in one Runt, and in the Bussorah 

 Carrier, there were only eleven. In Tumblers there are either eleven, 

 or twelve, or thirteen sacral vertebrae. 



The caudal vertebrae, are seven in number in the rock-pigeon. In 

 Fantails, which have their tails so largely developed, there are 

 eight or nine, and apparently in one case ten, and they are a little 

 longer than in the rock-pigeon, and their shape varies considerably. 

 Pouters, also, have eight or nine caudal vertebrae. I have seen eight 

 in a Nun and Jacobin. Tumblers, though such small birds, always 

 have the normal number seven ; as have Carriers, with one exception, 

 in which there were only six. 



The following table will serve as a summary, and will show the 

 most remarkable deviations in the number of the vertebrae and ribs 

 which I have observed : — 



