110 PTERYLOGRAPHY. 



II. PIGEONS WITH SIXTEEN RECTRICES. 



The two species of this group known to me, namely, C. militaris and C. coronata, are 

 further very remarkably distinguished from the other Pigeons by the complete absence of the 

 oil-gland. The former, however, agrees perfectly in its pterylosis with C. livia, but nevertheless 

 differs from it in the form of the first three remiges, which are remarkably pointed, and of which 

 the third 'possesses a very singular emargination at the base of the inner vane. C. coronata 

 differs very materially even in the structure of the tracts from all other Pigeons known to me, in 

 this respect rather approaching the Gallinaceous Birds. Thus it has on the neck an almost 

 uninterrupted plumage, the lateral neck-spaces being remarkably short, and the division of the 

 inferior tract only commencing immediately in front of the furcula. Each limb passes on the 

 breast in a very broad form, and sparsely feathered, and for some distance increases in width. 

 Then it divides into three branches, the innermost of which, nearly approaching the crest of 

 the sternum, is the true main stem, and consists of the greatest number (three to four) of rows of 

 feathers ; it is continued uninterruptedly on to the belly, when it turns a little outwards, and 

 then returns in a curve to the anus. The second or middle branch is more sparsely feathered, 

 but narrower ; it runs parallel to the main stem, and terminates at the margin of the musculus 

 pectoral-is major. This is the true outer branch of the inferior tract. The third branch, the 

 outermost in its position, originates nearly in the region of the axillary joint, and is strongly but 

 very sparsely feathered ; it turns more towards the inside of the upper arm, and runs down upon 

 this as the hypopterum. The rest of the pterylosis has nothing peculiar. The dorsal tract is strong 

 in the anterior, furcate portion ; in the posterior portion, cleft longitudinally, sparsely feathered, 

 and dilated externally, but not connected with the rather strong lumbar tracts. A weak plumage 

 is presented by the tibiae. The wings bear twenty-five remiges, the shafts of which are quadran- 

 gular, and have tJiree furrows on the flat lower surface, one in the middle and one on each side ; 

 their form is not so narrow and acute as in other Pigeons, and the whole wing is more rounded. 1 



2. PTEROCLES. 



In this genus, of which I have examined three species, namely, P. coronatus, exustus, and 

 setarius, the pterylosis on the ventral surface (Plate VII, fig. 3) agrees pretty closely with that of 

 Columba livia ; but the uniform breadth and parallel-sided form of the bands of the inferior tract, 

 which has not the least indication of an outer branch on the breast, may furnish a good distinctive, 

 character. Above, at the shoulder-joint, it has beside it a few weaker feathers, which unite it 

 with the axillary tract ; the hypopterum, however, is not connected with it, but runs down beside 

 it on the margin of the musculus pectoralis major. The dorsal surface (Plate VII, fig. 4) presents 

 several distinctions, especially 1, the shortness of the lateral neck-space, which reaches only to the 



In its internal structure Columba coronata less strikingly resembles the Gallinaceae, especially in 

 having no traces of c<eca, rudiments of which are always present in the other Pigeons. The gall- 

 bladder is also entirely deficient. 



