342 OSTEOLOGY OF PARID^, SITTA, AND CHAMPA LUCAS. 



a iiou-pueumatic sternum with a iion-pueuinatic luimerus, exceptions to 

 this are by no means rare, and that the character is of little taxouomic 

 value. 



To briefly sum up, the family Paridcv as it now stands comprises birds 

 differing very decidedly in cranial character, and while the genera Parus, 

 Auripariis, ^^githahis, and PsaltrqmrusmayhecTSLmo\og\(iiiUy(\\?[guose{\, 

 I confess my inability to assign osteological characters to the grou]). 



That the group is not a natural one I should hesitate to assert, but it 

 is by no means so homogeneous as the Swallows, Wrens, or Thrushes, 

 so far as I have studied them. 



The genus Sitta is sometimes placed among the Paridw, but, taking 

 Sitta caroUnensis as a typical member of the genus, it differs from the 

 Titmice and especially from Parus in many important particulars. 



The skull of Sitta resembles that of Parus in having a nearly closed 

 interorbital septum and broad prepalatines. On the other hand, the 

 skull of Sitta is slightly depressed instead of elevated, there is no fronto- 

 nasal nor maxillo-premaxillary hinge, the narial openings are elongate 

 ellipses, the nasals are very peculiar in form, with the external process 

 carried for a considerable distance along the premaxillary, and the 

 transpalatines and postpalatines are but slightly bent downward. 



The prepalatines of Sitta too overlie and fuse with the premaxillaries, 

 while in the Paridcv the prepalatines ruE along the inner edge of the 

 premaxillaries and the bones are soldered together by the deposition 

 of osseous matter in the surrounding membrane. 



Sitta also has what is unusual in the smaller Passeres, a large, free 

 lachrymal, much as in the Corvida', and the quadrate is so compressed 

 vertically that the pterygoid lies immediately under, and almost in con- 

 tact with, the ascending process, as in the Capriniulgida'. 



The pelvis of Sitta is anteriorly much narrower than in any of the 

 Paridw, the ischium and pubis project farther downward and backward 

 than in this group, and the obturator foramen is connected with the 

 very large obturator space. 



Fig. 5. — Dorsal aspect of left ■wings of Sitta caroUnensiq and Pants bicolor. Enlarged. 



Sitta, moreover, is peculiar in having — compared with the humerus — 

 a somewhat elongate fore arm and raanus, differing in this respect from 

 the Tits, and very much resembling the Corvidce. 



