208 STRUCTURE AND CLASSIFICATION OF BIRDS 



thirteen or fourteen in other Coraciid&e. The atlas (Coracias) 

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

 hsemapophyses. On C13 and 14 there are also a pair of 

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

 hsemapophysis, which, in the case of C14, arise from a 

 common base with it and on Dl from its tip. 



In Eurystomus the atlas is perforated. Four (Lepto- 

 sonius ! ) 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 Coracias, 

 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 

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

 Old-AVorld family, ranging through the Patearctic, Ethiopian, 

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

 predominating in the Ethiopian. 



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

 rectrices are twelve ; the feathers have an aftersliaft. The 

 pterylosis (described by NITZSCH and by myself' 2 ) is as 

 follows : 



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

 the neck with the ventral tract. About halfway down the 



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

 figured by MILNE-EDWARDS in the Histoirc Naturdl' tic Madagascar. See also 

 for the family NITZSCH and GIEBEL, ' Znr Anatomic der Blauracke,' Zcitschr. 

 f. d, gcs. Naturw. x. p. 318. 



- In anatomical preface to DKESSEH'S monograph. 



