898 DR. R. W. SHUPELDT ON THE OSTEOLOGY OF THE [DcC. 1, 



the essential characters of the hasal aspect of tlie skull as found in 

 the typical Swifts are present in Punyptiht, and they perfectly agree 

 in most important points with the same characters as described by 

 Professor Huxley for Cypsehis apus (figs. D and E). 



The vomer ( Vo) is long and narrow, being deeply cleft behind 

 where it straddles the rostrum of the sphenoid. Either limit is 

 carried back as far as the palatine head of the corresponding side, 

 with which it firmly articulates, as well as with the initial portion 

 of its ascending process. Anteriorly, the vomer dilates into a 

 liorizontal, triangular extremit}-, the line of the base being in front, 

 its angles just resting, one on either side, on the upper edges of the 

 broad maxillo-palatines, while the apex merges into the cleft portion 

 which extends backwards. 



A ma.riUn-piilniive (jV.rp) has the form of a sjiherical triangle, 

 is notably well developed, but does not meet its fellow in the median 

 line, the interval being s))anned by the vomer, as just described. 



The palatines (PI) are ])rincipally in two horizontal planes, and 

 either one lias a very characteristic form in the Swifts, which is 

 nearly approached by the Swallows. Its inner margin is deeply 

 cleft, giving rise to an anteriorly directed process that is quite 

 striking in the CiipseVulec, though it amounts to nothing more tban 

 an exaggeration of a similar condition found in the Passeres. 



The narrow palatine body merges anteriorly into the premaxillary, 

 and as it passes forwards to do so, undcrlaps the great tuberous 

 antorbital ; while further on, it shuts out of sight from this view the 

 connection between the vomer and tlie maxillo-palatine. 



Another exaggeration of a Passerine character of the palatine, seen 

 in the Swifts, is the form assumed b}' the postero-external angle of 

 the bone. It is in them produced into a well-marked ol)long process 

 directed backwards and outwards (see figs. D, E, and F). 



In the Passerine birds generally the jialatines have but one point 

 where they come in contact, and this is at their heads under the ros- 

 trum, where they articulate with the pterygoids. This applies also 

 to the Swallows, while in Fanyptila, and presumably in other Swifts, 

 these bones fail to meet even here, being separated by quite an 

 appreciable interval (fig. D). We have already seen that they are 

 very widely separated in Trochilus at this point. 



A pterygoid (fig. D, pt) is a very long, slender, and straight rod of 

 bone, having the same essential characters and making the same style 

 of articulations with quadrate and palatine, as in the typical Passerine 

 birds. 



In most particidars of any importance, so far as the basis cranii, 

 the rostrum, ethmoid, and all other parts of the i-kull of Panyptila 

 are concerned, they make no great departures from the generalized 

 Passerine skull, and they are by no means very different from such 

 characters as they are found in Hirundo. Indeed, so far as t.his part 

 of the skeleton goes, my studies of the osteology of American €yp- 

 selidcp and Hirnndihidce fully confirm Professor Huxley's investig-a- 

 tions ni that direction, who long ago pointed out the close relation- 

 ship of these two groups of birds (P.Z.S. lsG7, p. 4;')2). 



