310 



ZOOLOGY. 



(Fig. 161), they remain distinct, and preserve their mobility. 

 The lumbar and sacral vertebrae unite into one ; the coccygeal 

 are small and moveable, the last generally larger than the 



Fig. 285.--Breastbone of Swan. 



Fig. 286. Merrythought of 

 the Turkey.* 



others, and is raised into a crest. It 

 supports the large feathers of the 

 tail (Fig, 283). 



430. The ribs of birds show 

 some peculiarities tending to give 

 solidity to the chest or thorax. The 

 cartilage uniting the rib to the 

 sternum is osseous in the bird, and 

 each rib has a process, which running 

 backwards over the other rib, so 

 overlaps them that all the ribs sup- 

 port each other. 



But the most remarkable part of 

 the skeleton of the thorax is the 

 sternum (Fig. 287), which, giving 

 attachment to the muscles used in 

 flight, assumes ..an extraordinary 

 development, enclosing not only the 

 thorax, but a large part of the 

 abdomen. In the cassowary and 

 ostrich (Fig. 161) which do not fly, 

 the sternum has no external crest, 

 and the wings are rudimentary ; but 

 this crest exists in other birds, and 



* A very prevalent vulgar error is that the turkey has no merrythought, 

 this being the common name given to the clavicles which rest on the 

 sternum. Subjoined is a drawing of the furculum, or "merrythought" of 

 the turkey, and of the clavicles supposed to be wanting. E. K. 



