REPORT ON THE ANATOMY OF THE PETRELS. 47 
developed transverse processes, and between their centres inferiorly small chevron bones, 
smallest anteriorly, larger and double posteriorly, are developed. The last of these 
may, apparently, anchylose with the body of the corresponding vertebra. The pygostyle 
is long and compressed. The diving Pelecanoides has, it will be noticed, a greater number 
of vertebree (9) in its tail than the other forms. 
TABLE SHOWING THE NUMBERS OF THE VERTEBR&, Rres, AND UNCINATE PROCESSES. 
Total | 
Name. Cervical.| Dorsal. | Sacral. | Caudal. aS | Ribs. Uncinate Processes, | 
bre. || 
| 
Oceanites oceanicus, . : 2 15 6 9 8 38 8 (2+6) | 5 (15C.1-4D.), 
rarrodia nereis, . : é : 15 6 9 (2) (2) 7 (1+6) | 6 (15C.1-5D.) 
Fregetta melanogastra, . ¢ : 15 6 5 8 38 7 (1+6) 5 (1 - 5D.) 
Cymochorea leucorrhoa, ; . 15 7 10 7 39 8 (1+7) 6 (1-6D.) 
Procellaria pelagica, . : : 15 7 9 7 38 8 (1+7) 6 (1-6D.) 
“ Estrelata grisea” (a), : : 15 ie Bl i 40. | 8 (1+7) 5 (1 -5D.) 
> . (b), ; t 15 8 10 8 41 9 (14+8) 6 (1-6D.) 
Majaqueus equinoctialis, — . : 15 8 i 7 41 9 (1+8) 6 (1-6D.) 
Adamastor cinereus, . : é 15 7 12 7 41 8 (1+7) 5 (1-5D.) 
Pufinus anglorum, : ‘ : 15 7 12 8 42 8 (1+7) 5 (1 -5D.) 
»  obscurus, : ° : 15 7 11 8 41 8 (1+7) 5 (1—5D.) 
Daption capensis, P ; ¢ 15 7 11 7 40 8 (1+7) 6 (1-6D.) 
Acipetes antarcticus, . ‘ ; 15 7 11 7 40 8 (1+7) 6 (1—6D.) 
Thalasseeca glacialoides, ; : 15 Uf 11 8 41 8 (1+7) 5 (1-—5D.) 
Fulmarus glacialis, —. : : 15 7 11 8 41 | 8(1+7) 5 (1 - 5D.) 
Ossifraga gigantea, ; : ; 15 7 11 7 40 8 (1+7) 5 (1-5D.) 
Prion desolatus, . : ‘ 5 15 7 10 if 39 9(2+7) | 6 (15C.1-—5D.) 
Pelecanoides urinatriz, . : ; 15 7 10 9 41 |) 8(1+7) 6 (1-6D.) 
Diomedea exulans, é : - 15 7 12 6 40 8 (1+7) 5 (1-5D.) 
is brachyura, . : : 15 7 12 14 41 8 (1+7) 5 (1-—5D.) 
Thalassiarche melanophrys, . : 15 a 12 7 41 8 (1+7) 5 (1-5D.) 
Pectoral arch.—The sternum (Pl. VII.) is usually rather broad and short, much longer 
in Pelecanoides than in any other genus, with a well-developed keel, and a short, but dis- 
tinct manubrium—obsolete in Pelecanoides. The costal processes are triangular in shape, 
directed outwards, or in the Oceanitide and Pelecanoides, forwards and outwards. The 
anterior margin of the keel is more or less excavated, with its lower angle produced 
forwards, most so in Puffinus anglorum. In Pelecanoides (Pl. VII. figs. 3, 4) this part 
articulates with the clavicular symphysis, instead of being merely connected to it by 
ligament, as in the other forms. The coracoidal grooves are oblique backwards, and 
present two distinct articular areas for the articulation of the coracoid bone. The sides 
of the sternum usually converge towards the lower end of the costal process, and then 
diverge again to their posterior extremities. As may be seen from the figures of Plate VII. 
