190 STRUCTURE AND CLASSIFICATION OF BIRDS 



undoubtedly nearly related to the Capitonidre, and show 

 slighter but still recognisable points of affinity with the 

 Passeres. The toucans, which are purely tropical American, 

 consist, perhaps, of only one well-marked genus, Rliamphas- 

 tos, which, however, has been subdivided into Pteroglossus, 

 Aulacorhamphus, Selenidera, and some others. The toucans 

 have a tufted oil gland, an aftershaft, and ten rectrices. 



The pterylosis (cf . NITZSCH) is characterised by the wide 

 lateral neck spaces. 



The dorsal tract does not divide on the neck, nor is it as 

 a rule l continuous throughout. There is a break between the 

 straight anterior portion and the Y-shaped posterior portion. 

 The ventral tract divides in the middle of the neck, and 

 there is a strongly marked outer branch to the pectoral 

 tracts. The femoral tract does not, according to my own 

 experience, arise so early from the spinal tract as NITZSCH 

 figures. 



The intestinal tract of the toucans is short but volumi- 

 nous, eighteen inches in Rliampliastos dicolorus, nineteen 

 inches in R. carinatus. There are no caca. 



The proventriculus is zonary ; the stomach is a weak 

 muscular bag. 



In the liver the right lobe is larger than the left, three 

 times larger in R. carinatu*. 



The most characteristic feature in the anatomy of the 

 family concerns the gall bladder ; this has been principally 

 investigated by FoKBES. 2 It will be seen that the gall bladder 

 is tubular, and of very great length (4'15 inches in a specimen 

 of Rliampliastos dicolorus}, as also in the CapitonidcB and a 

 fewPicidae (qq.v.) I found in Eh. tocard an exceptional state 

 of affairs. As in all (?) toucans, the gall bladder is long, 

 but from the upper extremity two separate cystic ducts arise, 

 which soon fuse to separate again ; :J they open, however, in 



1 NITZSCH mentions as an exception an unidentified species. And in 

 Selenidera and Aulacorliamplius I could find no break. 



- ' Note on the Gall Bladder, &c., of the Toucans and Barbets,' P. Z. ,S'. 

 1882, p. 94. 



3 This may perhaps be regarded as a faint indication of the rctc found in 

 some reptiles. 



