322 PROFESSOR OWEN ON THE SKELETON 



The first fiee caudal has a depressed subquadrate centrum, broad and depressed 

 diapophyses inclined backward, with terminal pelvic articulations as above stated. 

 The second, third, and fourth caudals diminish in size, and more so in the breadth of 

 the diapophyses, which end freely. 



A small haemapophysial tubercle is wedged between the second and third caudal 

 centrums ; a larger plate is between the third and fourth caudals ; it begins to be com- 

 pressed between the fourth and fifth caudals. The next hsemapophysis resembles a 

 short compressed spine, inclined forward ; the fifth and sixth hsemapophyses diminish 

 in size; the seventh and eighth are elongate bones underlying the centrums, with which 

 they are nearly coextensive. One sees that the under and fore part of the terminal 

 anchylosed mass of caudals is a confluent haemapophysis of like shape. 



The diapophyses increase in length from the fourth to the seventh caudalsj these 

 decrease in the eighth and ninth, and disappear in the tenth. The neural spines are 

 stumpy and thick on the anterior caudals, look longer, because thinner, on the succeeding 

 ones to the ninth, are short on the tenth and eleventh, and are represented by a con- 

 tinuous ridge on the terminal coalesced vertebrae. The length of the caudal region is 

 3 inches 9 fines. 



From the position of the acetabula, and prior to sacral confluence, there would be 

 shown eighteen free caudal vertebrae in the young Garfowl : one sees that if these 

 vertebrae had continued free and participated in the rate of growth of the antecedent 

 centrums, how similar a caudal appendage to that of the ArchcEoptcryx^ would have 

 resulted. 



The sternum (PI. LI. hs, 6o ; PI. LII. figs. 1 & 2) is long, narrow, entire, with the 

 ked (hs) equalling in depth the breadth of the mid part of the bone. The epister- 

 num (e) is short, compressed, wedge-shaped, with its thin obtuse apex curved a little 

 down and back. The "coracoid" grooves (6) are separated from each other by the 

 base of the episternum (e) : each is divided into an inner and an outer articular facet ; 

 the inner one (PI. LII. fig. 2, b) is the largest, and is subtriangular, the broadest part 

 being sustained by a kind of buttress-like prominence, each buttress (/, /) diverging 

 from the fore part of the origin of the sternal keel {hs). The outer facet (ib. b') is 

 bounded by a short plate in front, and by the base of the costal process behind. 



The "costal" process2(c?) is subcompressed, triangular, with an obtuse apex directed 



' Phil. Trans. 1863, p. 44, pi. 1. 



' See the definition of this and the other processes in art. Aves, ' Cyclopaedia of Anatomy and Physiology,' 

 vol. i. 8vo, 1836. The sternum of the bird is not the homologue of the plastron of the Tortoise; it is never 

 developed from longitudinally consecutive series of lateral elements such as represent the hsemapophyses of 

 certain dorsal segments in Chelonia. In most birds ossification of the sternum begins from a pair of centres, 

 which, meeting and coalescing at the mid line, thence extend into the cartilaginous basis of the keel. The extra 

 pair in the anomalous sternum of Gallinse is special and exceptional in the Bird class. The application of the 

 names of the elements of the Chelouian plastron to parts of the Avian sternum is to be deprecated, save in the 

 case of the episternum, the bifurcate character of which is shown by bone in Passerines. 



