154 PTERYLOGRAPHY. 



Guillemots, such as Uria troile, U. grylle, and U. die, is decidedly twelve. I found the same 

 number in Phaleris cristatella and Alca tor da; but Alca impennis has eighteen, which, however, 

 are but small and weak. The oil-gland in all these genera is of comparatively small size, broadly 

 cordate, deeply bilobed, and rounded off anteriorly ; its body bears semiplumes, and its short 

 thick mamilla a strong circlet of oil-feathers round the orifices, the number of which amounts to 

 four on each half, at least in Uria troile. I have, however, been able to examine the organ in 

 question carefully only in this species. 



B. The plumage shows no distinction between tracts and spaces, but is of uniform structure 

 throughout. 



In the genera Spheniscus (demersus) and Aptenodytes (patagonlcus) the con tour- feathers stand 

 with the most perfect uniformity over the whole surface of the body, and not the smallest trace of 

 a space can be detected anywhere, even in the axillary cavity. They are very closely approximated, 

 but arranged, in the manner previously described, in definite rows. The feathers themselves have 

 a narrow lanceolate form, and a very broad flat shaft, convex beneath, in which the ordinary 

 furrow of the lower surface is wanting, and from which the barbs issue like splinters of the 

 superior horny lamella. At the extremity of the feather the barbs are rigid, and rather 

 bristle-like, although flat ; at the lower part they become softer and downy. The distinctly 

 recognisable aftershaft has exactly the same texture. Beneath the latter follows the short, 

 fusiform, inflated tube, discriminated from the shaft by a deep constriction ; the main shaft 

 does not, as usual, meet with this in the same axial direction, but at a decided and very perceptible 

 angle. Between the contour-feathers there are, of course, down-feathers everywhere. True, 

 specially formed remiges cannot be detected in the close scaly covering of the wings, but in the 

 tail stiff rectrices may be distinguished. Their number in A. patagonicus is thirty -two or more. 

 The oil-gland is not wanting, but is difficult to find on account of the dense and rigid covering 

 of feathers which conceals it. When it is discovered the dense circlet of oil-feathers is also soon 

 recognised ; its feathers are distinguished from the rest of the plumage by finer but still rigid 

 shafts, and much longer, capillary, soft barbs, which are downy below. I could not exactly 

 ascertain the number of orifices. 



Besides these two species I have been unable to examine any member of the group of 

 Penguins. 



