. The structure and classification of birds . h thetemporal muscles are partly attached. The bone varies insize, is not ankylosed to the skull, and is probably to belooked upon as an ossification in the septum between thetwo muscles. In these birds alsothe quadrate is peculiar in form inthat the anterior process is shortand slender and at right angles tothe rest of the bone. Sula is nearest to Phalacroco-rax. It has the same peculiarform of the quadrate bone, andthe equivalent of the small boneseated upon the jugal bone isapparently there, though anky-losed. The nostrils too are re-duced to a
. The structure and classification of birds . h thetemporal muscles are partly attached. The bone varies insize, is not ankylosed to the skull, and is probably to belooked upon as an ossification in the septum between thetwo muscles. In these birds alsothe quadrate is peculiar in form inthat the anterior process is shortand slender and at right angles tothe rest of the bone. Sula is nearest to Phalacroco-rax. It has the same peculiarform of the quadrate bone, andthe equivalent of the small boneseated upon the jugal bone isapparently there, though anky-losed. The nostrils too are re-duced to a mere pinhole, as inPlotus. The palatines agree ab-solutely with those of Phalacro-corax and Plotus, but the interor-bital septum is not so completelyvacuolate. It rises up, more-over, in front, as in Pelecanus,and a faint crest from the pala-tines ascends into the lacrymal is, however,different; the orbital part issmall, but the descending bar is large and joins the jugal;the ectethmoids appear to be deficient as bony Pig. 192.—Skull of Phaeton(atteb Beddabd). LbtteeingAS IN Fig. 191. J. A. Jeifkies, The Osteology of the Cormorant, Science, ii. p. 739, 59, 274 ; Gill, Osteology of the Cormorant, ibid. iii. p. 404 ; Shufeldt, Remarks upon theOsteology of Ph. bicrisiatus, ibid. ii. p. 640, and Osteologyof the Cormorant, ibid. iii. p. 143; Dollo, Bull. Mus. Roy. Belg. iii. 1884, This bone (xiphoid, Yaeeell; nuchal, Mahsh ; intranuohal, Dollo) hasbeen wrongly compared with the post-occipitals of dinosaurs. It is merely asesamoid. LncAs, Description of some Bones of Pallass Cormorant (), P. U. S. Nat. Mus. xii. 1889, p. 88. 412 STKUCTURE AND CLASSIFICATION OF BIEDS The lacrymal, as in Pelecamis and Fregata, is deeply notchedlaterally. MiVAET, from his investigations into the axial skeletonof this group/ set aside Phaeton and Fregata by reason oftheir possessing twelve or thirteen cervical vertebrae andthe doubly notched (on
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbirds, bookyear1898
