. The structure and classification of birds . ankylosed with the orbital margin. Cere-opsis has (among the genera which I have examined) a skull H II 1?. Fin. 225.—VENTRALVIEW OF SAME. IrtUTsasiuti^. --4. 468 STRUCTURE AND CLASSIFICATION OF BIRDS which is peculiar in that posteriorly the lacrymal is freefrom the orbital wall, but is fused with a process of thefrontal at the anterior end of the supra-orbital impression,leaving (as in Cliionis and some other birds) a InCereopsis the descending process of the lacrymal curves back-wards and comes near t
. The structure and classification of birds . ankylosed with the orbital margin. Cere-opsis has (among the genera which I have examined) a skull H II 1?. Fin. 225.—VENTRALVIEW OF SAME. IrtUTsasiuti^. --4. 468 STRUCTURE AND CLASSIFICATION OF BIRDS which is peculiar in that posteriorly the lacrymal is freefrom the orbital wall, but is fused with a process of thefrontal at the anterior end of the supra-orbital impression,leaving (as in Cliionis and some other birds) a InCereopsis the descending process of the lacrymal curves back-wards and comes near to the zygoma; 2 the junction iscompletely effected, and there is ankylosis, in Denclrocygna. The ectethmoids of the Anseres are often largely deficientas ossifications; when present they are thin-walled bubble-like structures, coming into relation with the interorbital septum is generally very complete ; but itis largely vacuolate in Mergus and Eiziura. The following table shows the number of cervicalvertebra and the condition of the hsemapophyses andcatapophyses in a series of anserine birds :- — C. V. f Hyp- Cat. nearlyunite Po
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectbirds, bookyear1898
