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Show 1894.] OP THE STEGANOPODES. 161 Ornithotomists are agreed that the Steganopodes, considered as a whole, constitute a well-defined group, but beyond this the majority are reticent as to the question of the affinities existing among the families and genera composing it, and its relations as a whole to other avian groups in the system. If from among the Pelecanidce we select the genus Phalacrocorax, there is no doubt, so far as its osteology indicates, that it is closely related to the genus Anhinga. This, as has been shown in my work, is evident from a direct comparison of the corresponding bones of the skeleton of any species of Cormorant with those of the skeleton of Anhinga. On the other hand, and by similar methods, there is no disguising the kinship existing between Phalacrocorax and Sula, although the gap between these genera is somewhat greater than that between the Cormorants and the Anhingas. Pelicans of the genus Pelecanus are aberrant forms which, as osteologically indicated, have varying relations with all three of the genera thus far mentioned. They are, however, apparently more nearly related to the Suliclce than to the Cormorants. From the Pelecanoidea the passage to the Phaethontoidea is not far to seek, for, upon comparing the corresponding bones in the skeleton of such a Gannet as Sula brewsteri with those of Phaethon fiavirostris, we are at once confronted with so many points of similarity as to leave no doubt upon our minds that it is between the genera and families represented by such species as these that the linking of the two groups takes place. This is important, for in another direction we are led on the one hand through Phaethon to the suborder Longipennes, and on the other to the suborder Tubinares-Phaethon fiavirostris having some osteological characters that strongly suggest Larine affinities, and still more that bring to mind the skeleton of a Puffinus. With their distinct maxillo-palatines, their perforate nostrils, their hardly coalesced palatines, their four-notched sternum, and with their ilia widely separated from the " sacral crista," taken in connection with numerous other important skeletal characters, the Tropic Birds are fully entitled to rank as a superfamily- the Phaethontoidea. There can be no doubt about Fregata, for the skeletal characters seen in its skull, its sternum and shoulder-girdle, its pelvis and limbs, and in its trunk skeleton, as described in detail in my account, stamp it at once, not only as being a form having many skeletal characters completely at variance with those found in average steganopodous birds-such as Cormorants and Gannets-but as a type likewise for which a superfamily must be founded in order to show that these striking departures are fully appreciated by the student of its osteology. As indicated in our scheme above referred to, this superfamily may be designated Fregatoidea. The pelvis in Fregata is decidedly more like the pelvis in Phaethon than that bone in other Steganopodes. In its extra- PROC. ZOOL. S O C - 1894, No. X L 11 |