1905. ] OSTEOLOGY OF THE EURYLEMIDS. 39 
corresponding to the sub-crescentic plates of Calyptomena. These 
hemipterygoids, in both the Eurylemid and Cotingid forms, 
articulate with the palatines, in the adult, by means of an oblique 
suture. 
Corydon and Cymbirhynchus difter in no essential features from 
Calyptomena. 
The quadrate is peculiar in that, in common with the Tyrannide 
and some other Passerine forms, it sends out a strong spur for the 
articulation of the quadrato-jugal bar. This spur projects like a 
buttress laterad of the outer condyle for the lower jaw. The 
squamosal and otic heads are closely approximated. The former 
is wedged in between a prominent processus articularis squamosr 
behind, and an equally well-developed processus articularis zygo- 
maticus in front. In Corydon these processes are expanded 
laterally so as to overhang the head of the quadrate, but at the 
same time they afford this element a greater freedom of movement 
than in Calyptomena. Cymbirhynchus and Eurylemus are inter- 
mediate in character in this respect. 
The Mandible. 
The mandible, in the Eurylemide, is much bowed outwards 
to a very considerable extent. In Calyptomena it has only a 
relatively small symphysis: is truncated posteriorly, and shows 
little or no trace of the separate elements of which it is composed. 
The internal angular process is moderately well developed, and is 
perforated by a small pneumatic foramen. The rami, in their 
general shape, are rod-like, and slightly compressed laterally. 
In Corydon and Cymbirhynchus, however, there is an abrupt 
transition between the malar region of the mandible and that 
portion covered by the rhamphotheca, which is most markedly 
thicker and broader than the hinder region. The symphysial 
region is very broad and spoon-shaped. ‘The internal angular 
process is more spine-like than in Calyptomena, and there is a 
feebly-developed posterior angular process. 
The Hyoid. 
The hyoid of the Eurylemide resembles that of the higher 
Passeres. The basihyal (os entoglossum) is made up of a pair of 
boomerang-shaped ossifications placed dos @ dos, so that a long 
free process is produced backward beyond the articulation with 
the basibranchial 1. Basibranchials 1-2 are fused; the latter, 
however, is a long cartilaginous style. The ceratobranchial and 
epibranchials are of moderate length; the latter are cartilaginous 
at the free ends. 
In Corvus, for example, among the higher Passeres, the basi- 
hyals are long and straight, and run parallel with one another, 
yet so as to leave a median space between them. 
