212 STRUCTUKE AND CLASSIFICATION OF BIRDS 



genus. The last few tracheal rings are fused, but there is 

 not a complete pessulus. 



The motmots have fifteen cervical vertehrm. The atlas is 

 perforated by the odontoid process. Cl-5, C11-D3 have 

 median hypapophyses ; on C14-D2 are a pair of inferblateral 

 processes, which gradually approach the median line until 

 they spring from a common base in Dl, and are just visible as 

 rudiments towards the tip of the hsemapophysis of D2. In 

 Hylomanes there is also a double hypapophysis on CIO. Three 

 or four ribs reach the sternum, which has (Momotus) four 

 foramina, or {Hylomanes) two notches and two foramina, 

 and a bifid spina externa. The skull is desmognathous and 

 holorhinal. The lacrymals.are rudimentary ; the ectethmoids 

 are very small and do not nearly reach them. Nares 

 impervious, pervious in Hylomanes. 



The West Indian todies (Todidse) form a very distinct 

 family ; their structure has been chiefly investigated by 

 MuRiE ' and Forbes.^ They are small birds with feet in 

 which the syndactylism is more marked than in motmots and 

 some others. The annexed cut shows that the digits IV. 

 and V. are united together as far as the end of the third 

 phalanx of the one and the second of the other. The 

 oil gland is tufted. 



The skull is very imperfectly desmognathous. The two 

 maxillo-palatines are not united together; they are com- 

 pletely free from each other and from a median ossified nasal 

 septum. There seems to be no vomer. The descending 

 portion of the lacrymals is large and broad ; the ectethmoids, 

 on the other hand, are small. The interorbital septum is 

 widely fenestrate. There are fifteen cervical vertebrae. The 

 intestines are, according to Mr. Forbes, remarkably short, 

 not measuring altogether more than 3^ inches ; on the other 

 hand the cceca are as remarkably long (considering the sys- 



' ' On the Skeleton of Todus,' &o., P. Z. S. 1872, p. 664. 



2 ' On some Points in tlie Anatomy of the Todies (Todidte), and on the 

 Affinities of that Group,' ibid. 1882, p. 442. See also Eeighenow, ' Ueber das 

 Genus Todus,' &a., Journ. f. Ornith. xxxi. 1883, p. 430. 



