646 MR. A. H. GARROD ON THE HUIA BIRD. [May 21, 



The maxillo-palatines in their approximate portions are shorter 

 from before backwards than in Sturnus, and much resemble those 

 of Corvus. 



The antero-inferior processes of the orbit are large and spongy ; 

 they almost touch the zygoma. But the most characteristic portion 

 of the skull of Heterulocha is the occipital region ; and in this it 

 presents a great exaggeration of the peculiarities of Sturnus and 

 its allies. 



In Corvus (fig. 4) and most Passerines the digastric muscles oc- 

 cupy a narrow space intervening between the auditory meatus and 

 the mass of occipital muscles, not extending so high up the skull as 

 the latter. The occipital ridge encloses a space elongated from side 

 to side and of but little depth. 



In Sturnus the digastrics are much broader, and they narrow the 

 occipital space ; they also extend up the skull to so great an extent 

 that they nearly meet in the middle line above the origin of the 

 biventres cervicis muscles ; but in Heteralocha (fig. 3) they are of still 

 greater size, and meeting above the middle line they form a strong 

 ridge, which extends for some distance into the parietal region 

 vertically. This peculiar development of these muscles produces a 

 corresponding change in the shape of the space enclosed by the 

 occipital ridge. In Heteralocha it is almost circular, and it extends 

 some way above the foramen magnum. In Sturnus there is an 

 approximation to this condition. 



A vertical parieto-occipital ridge in many other birds closely 

 resembles that of Heteralocha ; but it is the median limit of the tem- 

 poral fossa in most. 



Correlated with this extensive digastric origin is a large surface 

 for its insertion. The angle of the mandible (see fig. 1, p. 647) is 

 prolonged directly backwards for this purpose, in a manner unique 

 among Passerine birds, but well seen in the Analidce. In Sturnus 

 the angle of the mandible is slightly prolonged backwards for a 

 similar purpose. 



In comparing the skulls of others of the Sturnidce the following 

 is a graduated series, based on the development of the digastric 

 fossae in those birds I have had the opportunity of examining, com- 

 mencing with Heteralocha and ending with Corvus. 



Heteralocha. Quiscalus, 



Sturnella. Cassicus. 



Stui-nus. Acridotheres. 



Icterus. Pastor griseus. 



Pastor ialla. Molothrus. 



Gracupica. Corvus. 



The palates in most of these birds were not in a fit condition for 

 study ; and, as will be clearly seen, geographical range has not been 

 attended to. 



In the sternum, Heteralocha differs in no important point from 

 Stuwius, except that the posterior notches tend to be converted into 

 foramina, as observed by Mr. Eyton in his ' Osteologia Avium.' 



