208 STRUCTUEE AND CLASSIFICATION OF BIRDS 



thirteen or fourteen in other Coraciidae. The atlas (Goracias) 

 i^ notched for the odontoid process ; C2-4, C10-D2 have 

 hffimapophyses. On 013 and 14 there are also a pair of 

 downward processes (catapophyses) , one on each side of the 

 hsemapophysis, which, in the case of 014, arise from a 

 common base with it and on Dl from its tip. 



In Eurystomus the atlas is perforated. Pour (Lepto- 

 somus ') or five (some other forms) ribs reach the sternum, 

 which is singly or doubly notched on either side, and has a 

 spina externa but no spina interna. The skull is desmogna- 

 thous, holorhinal, without basipterygoid processes. The 

 rollers have the same peculiar lacrymal that has been referred 

 to above in the kingfishers. The bone expands enormously 

 below and comes into near relations, but does not fuse, with a 

 slight ectethmoid ; the lacrymal reaches the jugal. Another 

 peculiarity of the coraciid skull is the very large postfrontal 

 process, which descends in a straight line and actually 

 reaches the jugal. These remarks apply not only to Goracias,* 

 but to Eurystomus and Atelornis, in which latter, however, 

 the postfrontal process is not quite so long. 



The family Meropidae consists of the genus Merops, and 

 of a few others which have been carefully monographed by 

 Drbsseb. Like the rollers the bee-eaters are an exclusively 

 Old-World family, ranging through the Palsearctic, Ethiopian, 

 Oriental, and Australian regions, but again, like the rollers 

 predominating in the Ethiopian. 



As to external characters, the oil gland is nude ; the 

 rectrices are twelve ; the feathers have an aftershaft. The 

 pterylosis (described by Nitzsch and by myself^) is as 

 follows : — 



The spinal tract is wide, and is at first connected round 

 the neck with the ventral tract. About halfway down the 



' The osteology (and some of the viscera) of Leptosomus is described and 

 figured by Milne-Edwaeds in the Eistoire NahweUe de Madagascar. See also 

 for the family Nitzsch and Giebel, ' Zur Anatomie der Blauraoke,' Zeitschr. 

 /. d. ges. Naturw. x. p. 318. 



^ In anatomical preface to Deessee's monograph. 



