1905.] OSTEOLOGY OF THE EURTL^MIDJi:. 35 



The cerebral fossce are relatively of considerable size, though 

 relatively smaller than in Corvus for example. Thus, in the 

 Euryl?emicl£e the cerebral fossa is only distinguishable from the 

 mesencephalic fossa by reason of the boundary-line of the 

 tentorial ridge. In Corvus the mesencephalic fossa forms a 

 totally distinct basin-shaped cavity, lying as it were within the 

 cerebral fossa, which dips down to the outer side and below the 

 level of the fossa in question in the form of a deep pocket. 

 Menura represents a half-way stage between the Oorvidse and 

 Euryl^emidcB. In Menura, moreover, the roof of the cerebral 

 fossa is mai'ked by a low ridge roughly dividing the fossa into 

 two equal parts. 



There is a well-developed bony/aZcc. 



The olfactory fossae are reduced to a pair of small pits. But 

 there are strong impressions of an olfactory tube to be found in 

 the fore part of the cerebral fossa of the Eurylsemidse. 



The Premaxilla. 



The premaxilla in the Eurylfemidae forms the major part of the 

 upper half of the beak. Hooked at the tip, and of extreme 

 breadth, it recalls in many respects that of many of the Ooraciidaj, 

 e. g. Eurystomus, on the one hand, and of some Oaprimulgi, 

 e. g. Podargus, on the other. When these several types come to 

 be compared, however, these resemblances will be found to be but 

 slight. 



More significant is the close resemblance to the Ootingidse. 

 This is well brought out in the skull of Calyptomena^ which, as 

 will be shown presently, presents many features in common with 

 Ghasmorhynchii/S. The number of other skeleton characters which 

 these two forms possess in common suggest affinity between the 

 two groups, rather than homoplasy. 



In Calyptomena, which I propose to take as the typical 

 Eurylpemid for the purpose of comparison, the body of the pre- 

 maxilla is moderately large. The nasal process, fusing with the 

 nasals, is sharply truncated caudad, and articulates with the 

 frontals by a hinge. In this respect the Eurylasmid skull re- 

 sembles that of the Podargidie, and not of the Coraciidse. 



The low position of the skull of Calyptomena is indicated by a 

 comparison of the narial aperture with that of the skulls of other 

 Eurylpemid genera. 



In Calyptomena the nasals are of the typical holorhinal shape 

 with an obliquely sloping descending process. The nasal fossa, 

 in the dried skull, is a long oval aperture showing, within the 

 cavity, a narrow ridge of bone continued from the palatal border 

 forwards to meet a low septum hanging from the middle line of 

 the nasal process of the premaxilla. The septum represents the 

 ossified remains of the septwm nasi ; the small plate of bone 

 running inwards from the level of the tip of the palatine is a 

 portion of the alinasal cartilage which has become ossified. 



3* 



