A.d.O Correspondence. [October 



Now in tlie skull of the Pifilo, which I have chosen for comparison, 

 each and all of these characters are just the reverse. There we find not 

 even a vestige of an osseous nasal septum ; nor does the fars fla^ia so 

 much as reach the jugal bar; nor are the postero-external angles of the 

 palatines bifurcated, but are on the other hand distinctly truncated from 

 without inwards and backwards; while in addition we find in this species 

 very conspicuous tympanic bullie, a large vacuity in the interorbital 

 septum, a narrow frontal region, and the secondary palatine processes 

 absent (Fig. 2). Both of these birds possess an elliptical vacuity in the 

 ramus of the mandible, on either side, but in Habia this bone is far 

 stronger with much deeper sides than we find it in Pipilo, and withal 

 is not a little difterent in shape. In both of these Finches, too, the 

 squamosal processes are very large (5«) ; while I may add that thus far it 

 is only in Habia melanocepkala, of all our Conirostres that I have de- 

 tected the secondary palatine processes. The characters of the skull in 

 Pipilo m. jnegalonyx are almost exactly repeated in the skulls of Pipilo 

 ci/lorttrus and Zonolric/iia coronala, though the skull in the first-named 

 species is considerably larger, and has the tympanic bullte markedly more 

 prominent; while in the case of the two species last named, both in point 

 of size and in all other details, it lies next to an impossibility to distin- 

 guish them. All North American Fringillidoe have an extraordinarily 

 minute occipital condyle, as compared with the size of the skull (see figs. 

 I and 2). 



Bv the easiest sort of intergradation the skull of Zo7iotrichia shades 

 into the skull of Chondestes, and an attempt to define the differences 

 between them would simply result in an enumeration of insignificant 

 details. As we pass to such a skull, however, as we find in Calcarius 

 lafponictts, a specimen of which species I collected in Wyoming in 1880, 

 and now have its skeleton before me, a few of the modifications in char- 

 acters so faintly forecast in Zowo/'/Zr ///<?, are here completed and stereo- 

 typed. The delicate, mesial ends of the maxillo-palatines are now- 

 enlarged and paddle-shaped; the antero-external angles of the vomer are 

 curled upwards and inwards; the palatines are well separated from each 

 other the entire length of the rostrum of the sphenoid, and their postero- 

 external angles each terminate in a needle-like point; and lastly, the 

 tympanic bullre cease to be a striking feature of the skull. And for 

 conirostral birds, the gap indicated by the characters of this part of the 

 skeleton, between such a type as Calcarius and Habia, is now of no 

 inconsiderable extent; I was almost about to say of family distinction. 



To see the tj'pified fringilline skull, however, we can turn to no better 

 example than exists in Calamospiza vielanocorys, — a true Bunting, if there 

 ever was one. Compact to a fault, and with all the bones stouter and 

 thicker than in any of the foregoing species, the skull of Calamospiza is 

 easily distinguished from the skull either oi Pipilo or of any of the true 

 Sparrows. In it the external nasal aperture upon either side, is circular 

 rather than elliptical, as it is in the Towhees and Zouotrichia. Compared 

 with its allies its characters are of excellent generic rank, if we may be 



