152 PTERYLOGRAPHY. 



Penguins (Spheniscus and Apterodytes), and may be distinguished from each other as follows, by 

 their chief characters. 



A. The plumage separated into definite tracts by several spaces, 

 a. The inferior tract-lands with no trace of an outer branch. 



This division includes the Grebes and Divers. In the form of their tracts they approach pretty 

 closely to the Steyanopodes, especially in the perfectly branchless inferior tract, which is formed 

 exactly as in the latter. The chief distinction of the two groups lies in the dorsal tract, inas- 

 much as here a division into the usual two parts may be clearly recognised, and this is absent in the 

 Stet/anopodes. The anterior part is stronger, and cleft at least from the commencement of the 

 trunk ; the posterior, much weaker part, certainly reaches to the anterior part, but is readily dis- 

 tinguished from it by the sparser distribution and weaker structure of the contour-feathers. The 

 neck is uniformly feathered, unless the spinal or inferior space is still continued upon it ; the 

 lateral neck-spaces are entirely wanting. The lateral space of the trunk is larger than in the 

 Steganopodes, and is particularly extended upon the back, completely separating the dorsal 

 tract, not only from the strong axillary tracts, but also from the weak lumbar tracts. An 

 upper wing-space is present beside the axillary tracts, but is very narrow behind. The wing- 

 feathers present nothing remarkable; but the small and soft, frequently indistinguishable, tail- 

 feathers remind us of the structure of the Ducks. With these the oil-gland is also in harmony 

 in its size and form, and especially in its small delicate mamilla, which has never more than two 

 orifices. 



1. Colymbus (PI. X, figs. 10 and 11). This genus, of which I have carefully examined the 

 large species, C. cristatus, and compared with it the smaller species, such as C. rubricollis, 

 minor, &c., is especially distinguished from the following one by the length of the two median 

 spaces. Both the inferior space, which becomes very broad posteriorly on the belly, and the 

 spinal space, reach far up upon the neck. Hence it may be that the limbs of the anterior part of 

 the dorsal tract advance but little beyond the commencement of the shoulder-blades, and the 

 remarkably weak, narrow, posterior part extends forward far between the shoulder-blades. The 

 oil-gland, on which this tract strikes, is much elongated, deeply divided, pointed anteriorly on 

 each half, furnished at the obtuse posterior extremity with a high, perpendicular mamilla, and 

 occupied internally in its greater part by a wide cavity. The circlet of oil-feathers is seated on 

 the middle of the conical mamilla, and at the apex of this we may with some trouble detect 

 two small orifices. I could not discover true (or rather well characterised) rectrices on the 

 small conical tail ; in the wing I counted in C. cristatus thirty-two remiges, of which eleven are 

 seated on the pinion, and the first is the longest ; the paraptera are of considerable size, and 

 consisjt of from eight to ten feathers. In C. rubricolHs I counted thirty remiges, of which eleven 

 were on the pinion ; in C. minor there were only twenty-six, but still eleven primaries. The 

 latter species has also a much broader oil-gland, which is obtuse and thicker in front, and its- 

 inner cavity is remarkably small. 



2. Eudytes (PI. X, fig. 12). From an examination of E. arcticus and septentrionalis (sive 

 rufoffiilaris), this genus is to be distinguished from the preceding by the following points : 1. The 

 inferior space is very narrow, remains of equal breadth throughout, and extends forward only to 

 the furcula. 2. The anterior part of the dorsal tract is cleft only to the shoulder, and its rather 



