438 



Correspondence. [October 



CORRESPONDENCE. 



\ Corresfioinit'uts are yequcalcd to write briefly ami to the point. No ntteiition v>i!l 

 he paid to anonymous cominnniiations.] 



The Osteology of Habia melanocephala, with Comparative Notes upon 

 the Skeletons of certain other Conirostral Birds and of Tanagers. 



To THE Editors of the Auk : — 



Dear Sirs : — To none others better than yourselves is the fact well 

 known, that whosoever has undertaken to compare the skulls of several of 

 the more nearly allied genera of our fringilline birds, with the view of 

 discovering distinctive characters among them, how next to hopeless that 

 person has found such a task to be. Among a large series of skeletons 

 before me I find such species represented as Zonotrichia coronaia, Chon- 

 destes grammacus, Habia melanocephala, Pipilo in. megalonyx, Pipilo 

 cklorurus, Piranga ludoviciaua., Calamospiza inelanocorys, Icteria v. 

 loiigicauda, Calcarius lapponicus, besides a host of other Passeres, in- 

 cluding the majority of the Crows, Jays, Orioles and their allies, Spar- 

 rows, Finches, and others, and it is truly wonderful to note the manner in 

 which the cranial characters, indeed the skull as a whole, in these numer- 

 ous genera, morphologically shades from one series of the more intimately 

 related forms into the group next most nearly allied, and so on, along 

 different lines, diverging as they do, from any well-defined genus we may 

 elect as our primary one for initial comparison. True as this is, however. 

 I find it none the less true that if we critically compare the skeleton of 

 some Finch, for instance, at one extremity of such a series, with the 

 skeleton of another conirostral species chosen from the other, important 

 differential characters may not infrequently be detected, which characters 

 are constant for the species, and of great value to the taxonomist of this, 

 in many cases, puzzling group of birds. It is vay object in the present 

 connection to point out some of the more available characters, such as I 

 refer to, and which I have met with in my osteological studies of this ex- 

 tensive group. In Habia melanocephala the skull as a whole bears a very 

 striking, though superficial, resemblance to that part of the skeleton in 

 certain Parrots, and when compared with the skull in such a form as 

 Pipilo m. megalonyx, for example (Figs, i and 2), presents us with some 

 excellent differential characters. Chief among them we find in the Gros- 

 beak to which I have invited attention that, in addition to its far more 

 massive osseous superior mandible, it possesses a complete hony seplum 

 nasi; the infero-external angle of a pars plana meets the jugal bar be- 

 neath it, and is produced backwards to no inconsiderable extent; the tym- 

 panic bullae are inconspicuous; the frontal region between the margins 

 of the orbits on the superior aspect of the skull is unusually broad; the 

 antero-external angles of the vomer are commonly produced, and fuse 



