OF THE VENTRAL TRACT. 29 



Trof/on (viridis, glocita/is, Plate IV, fig. 18), Prodotes (Plate IV, fig. 16), Prionites, Capita 

 (melanotis, Tamatia, Plate V, fig. 9), and Monastes (fuscus). 



8. With an indistinct branch, and resembling the last form, but with a true gap at the end 

 of the undivided gular portion ; the latter contains very large feathers, and clothes a pendent, 

 dewlap-like fold of the skin. This remarkable structure occurs in Coracina cephaloptera 

 (Ccphaloptcrus ornatus, GEOFFR.), Plate III, fig. 9. 



.9. With a double branch ; very narrow throughout, distinct on the throat, and already 

 divided into a right and a left band, with a broad median space : the outer branch is very short, 

 placed almost perpendicular to the main stem, and issues close to the knee-covert ; the internal 

 branch, which is longer, runs along the furctila, and starts from the lower extremity of the gular 

 portion. This form is seen in the genus Galbula (Plate IV, fig. 7). 



10. Very like the preceding form, but without the inner branch. This form occurs in 

 Merops (viridis, milieus) ; nearly the same arrangement is also met with in Coracias (from which 

 Colaris cannot well be separated generically), Plate IV, fig. 5 ; but the external branch is somewhat 

 longer, and nearly hooked, and the main stem is weakened from the breast downwards. 



11. With one branch; narrow but strong, often distinctly separated, even on the throat, and 

 soon afterwards cleft into a right and left band, which enclose the broad median space. The 

 truncal portion linear, weakened; the branch distinct, long, densely feathered, standing off 

 widely, truncated at the end, sometimes hooked. This form of the ventral tract occurs in many 

 Rapacious birds (Plate II), especially the Falcons (in which a notch, resembling an internal 

 branch, is observable at the lower part of the gular portion) and the Owls. It also occurs in the 

 genera Picus (Plate V, fig. 14), Yunx, Pogonias (sencgalcnsis and unidcntatus, but not sulcirostris), 

 Micropoffon (crythropygos, cat/cnnensis), and Bucco (armillaris, rost'icollis, sm&jlavifrons), Plate V, 

 fig. 1. 



12. With a branch, and similar to the preceding form, but sparsely feathered, and weakened 

 throughout ; the branch tolerably long, obtuse, and indistinctly limited on its inner margin. 

 This form occurs in the Parrots, but with the following variations : in some species, such as Psitt. 

 yaleritm and pertinax, the outer branch is very distinctly separated ; whilst in others, such as 

 Psitt. htematodes, pullarius, and crithacus, it is for the most part amalgamated with the main 

 portion ; a weak plumage having introduced itself between the branch and the main stem, which 

 gives this form a great resemblance to the first one. 



13. With a branch, like the eleventh form ; but the branch long or moderately long, dis- 

 tinctly bounded, obtuse, densely feathered; the truncal portion appears weakened, dilated behind, 

 and much approximated to its neighbour, especially on the breast, by which the ventral space is 

 rendered narrow, although it extends nearly to the throat. I have seen a ventral tract of this 

 kind in most of the Limicolcs seu Scolopacincs namely, in Numcnius, Charadrius, Tringa, 

 Scolopax (rusticula, in which, however, the division only commences at the lower part of the 

 neck) ; also in the Fulicarice, such as Grus (cinerea), Psophia (crcpitans, which possesses the 

 narrowest and most approximated pectoral bands, see Plate VIII, fig. S),Ralhis (Plate VIII, figs. 

 5 7), and Crex. The ventral tract is also similar in the Longipcnncs ; but in some of the larger 

 species, such as Lcstris cafarr/tactes (Plate IX, fig. 13), the pectoral band is so broad, and the 

 branch so short and narrow, that its formation agrees rather with that of the second form, such 

 as we have found in Diomedea. 



14. With a branch, broad, strong, and densely feathered throughout, divided by a narrow 



