AXIAL SKELETON OF THE PELECANID^E. 345 



A detailed description has been given by Brandt in the ' Memoires de 1'Academie,' 

 before referred to 1 , p. 127, with figures of the whole skeleton, the breast-bone, and a 

 back view of the pelvis, in pi. 2. 



I have been able to make use of the following skeletons for the purpose of com- 

 parison: A mounted skeleton, No. 1180 (P. carlo), and a natural skeleton, No. 1182 c 

 (P. Mcristatus), in the Museum of the Koyal College of Surgeons ; also a mounted 

 skeleton, a disarticulated natural skeleton, No. 68. 8. 16. 3 (P. carlo), a natural skeleton 

 from Chili, No. 76. 9. 26. 16, a disarticulated skeleton, No. 56. 11. 14. 17 (P. brasili- 

 ensis), and that of a small kind from the Upper Ucayle, No. 16. 3. 28. 17, all in the 

 British Museum. 



I am also indebted to Professor Garrod for the loan of a specimen. 

 The total number of vertebrae, without counting the pygostyle, seems to be from 

 forty-six to forty-nine. 



These vertebrae are subdivisible as follows eighteen cervical, two cervico-dorsal, five 

 dorsal, five lumbar, two lumbo-sacral, two sacral, seven or eight sacro-caudal, and five to 

 eight caudal, besides the pygostyle. 



There are constantly five dorsal vertebrae, and twenty cervical and cervico-dorsal 

 vertebrae taken together ; but there may be eighteen cervical and two cervico-dorsal 

 vertebrae, or seventeen cervical with three cervico-dorsals. The lumbar vertebrae are 

 generally five in number, but may be only four. The lumbo-sacrals may, by rare 

 exception, be reduced to one, or augmented to three. There may be but one vertebra 

 apparently distinguished as a sacral vertebra. The sacro-caudals and caudal vertebrae 

 taken together are generally as many as fourteen ; but they may be only thirteen, or as 

 many as sixteen ; and always either seven or eight of these ankylose with the pelvis, and 

 so come to be reckoned as sacro-caudal vertebrae. 



The whole axial skeleton, when compared with that of Sula, is a somewhat yet denser 

 structure ; and the various ridges and processes are sharper and relatively more developed. 

 Median hypapophyses are not only much more developed than in Sula, but even than in 

 Pelecanus, especially in the anterior sacral region. Hyperapophyses are also relatively 

 larger than in either of the former genera. The styloid rib-like processes are free, as 

 in Sula, and even somewhat longer relatively, being decidedly more slender. 



THE CERVICAL VERTEBRAE. 



These vertebrae, when compared with those of Sula, present a very close resemblance, 

 but are longer relatively and more hypapophysial, with a more slender and prolonged 

 styloid rib (p. 35). They are more numerous than in Sula or Pelecanus ; and thus the 

 sudden change of form takes place over vertebras more postaxiad than in those genera. 

 The ATLAS has its preaxial articular surface rather less circular, broader relatively 

 dorsally, and narrower ventrally. There is an odontoid foramen ; but it is less decidedly 



1 See above, p. 315. 



