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Show 1891.] SAUROGNATHISM OF THE PICI. 125 heavily with, which in time may have come to modify certain structures of the cranium, as has been pointed out by Garrod \ (7) It is quite characteristic of many of the skulls in the Pici that some of the free margins of the cranial bones, during the growth of the species, are prone to ossify by what may be designated as a " ragged border," and this will account for the minute granular islets of bone which occur along the mesial margins of the palatines ; they are the so-called " septo-maxillaries" of Parker,-but they really belong to the palatines. W e have found them to vary greatly in number, and in position in the same species. They are likewise adventitious ossifications, and they belong to the same category as the "Wormian bones" of anthropotomy. (8) Finally, as to the nasal labyrinth, we find nothing especially saurian beyond what we see in other highly specialized types of birds. Parker has said in the article " Birds" of the ' Encyclopaedia Britannica' (9th ed. p. 717), that " these birds are saurognathous in other respects, e. g., their nasal labyrinth is unusually simple. The ' inferior turbinal,' which has three coils in Rhea and Tinamus, and two in most birds, is in Gecinus merely bi-alate ; in lynx it makes less than a single turn, whilst the alinasal turbinal of that bird has two turns, and that of Gecinus one. Gecinus is in all respects the most specialized, Picumnus the most embryonic, and lynx the most passerine of the Celeomorphce. Also, in Gecinus the nasal labyrinth is most ossified, and in lynx least." This strikes us as rather peculiar logic when arguing for the saurian organization of certain cranial structures as seen in the Pici: especially when we come to recognize the relative position of Rhea in the system, and the high position held by the Passeres. Indeed, we must believe that too close study of a single set of characters stands in danger of making us blind to the significance of the tout ensemble of the characters presented on the part of the entire economy of the form examined. In his Linnean paper quoted above, Professor Parker says of Picumnus minutus that " I have had to work out the parts of this bird's palate from the fractured skull in a dry skin." His entire knowledge of the structures of this interesting genus of birds probably rested upon this examination. It is evident, then, what we most need now in this direction is a full description of the entire structure of several genera of the Pici, with the same for lynx and Picumnus, and these thoroughly compared with several of the Cotingidce aud Formicariidce and allied forms. As I have already remarked on a foregoing page, I have recently examined series of skeletons of many species of Woodpeckers found in the United States. The results of these investigations have been written out to form one of the chapters of m y work upon the Osteology of Birds of this country. Two sections terminate the chapter and they are herewith presented in advance of the publication for which they were written. 1 Coll. Sci. Memoirs, p. 117. |