THE NASUT^E. 145 



twenty-two remigcs, of which the first was equal to the fourth, and the second was the 

 longest. 1 



2. Pachyptila ceerulea presents exactly the pterylographic characters of Procellaria, except 

 that the short lateral neck-space advances but little forward, and the notch in the inferior tract is 

 so deep that its posterior or ventral half is completely separated from the anterior. The dorsal 

 tract presents nearly the same character as in P. gic/antea, but the division of the anterior part is 

 not so deep, and the lumbar tracts join the posterior part in the same oblique direction that I have 

 shown in Puffinus oliscurus (PI. X, fig. 3). The number of remiges is twenty-eight, and of these 

 the second is the longest. The rectrices are only twelve in number. 



3. Puffinus olscurus (PI. X, fig. 3). The feather-tracts of this genus differ from those of 

 Procellaria only in that the spinal space is situated higher up, reaching to the level of the 

 shoulder, but not passing beyond the commencement of the pelvic region. Here this tract, which 

 does not divide into two parts either as regards the position or the strength of the feathers, becomes 

 simple, and receives the somewhat sparsely feathered lumbar tracts, which are prolonged obliquely 

 from behind forwards. By this means they present precisely the reverse of the form represented in 

 Procellaria, and closely approach the formation of Pachyptila; a resemblance which is still further 

 increased by the short lateral neck-space, reaching only to the middle of the neck. Puffinus 

 obscurus has thirty remiges, of which the first is the longest ; and twelve tail-feathers, which, again, 

 furnishes an analogy with the second genus mentioned. 



4. Diomcdea. This genus, judging from an examination of D. exulans (PI. X, fig. 4) and 

 D. chlororl/yncha, has on the ventral surface precisely the pterylosis of Procellaria, except that the 

 inferior space only commences at the middle of the neck. The dorsal tract, however, presents 

 many peculiarities. The most important character is unquestionably the complete separation of 

 the anterior part from the posterior, the former being at the same time very strong and coarse, 

 and the latter weak. The former is broad, densely feathered, and furcate from the shoulder- 

 joint, with the extremity of each branch of the fork rounded off. The posterior part forms a weakly 

 feathered ellipse, extending from the extremity of the anterior part to the caudal pit ; its feathers 

 are placed, as usual, in oblique rows, converging in the middle, and running outward and back- 

 ward. At the caudal pit the ellipse contracts into a parallel-sided, strongly feathered uropygial 

 band, the extremity of which touches the large oil-gland. The latter is covered at the base with 

 semi-plumes, and has a strong circlet of feathers round the five openings of each half, which are 

 arranged in a perpendicular row. To these peculiarities are added very weak uniserial lumbar 

 tracts, closely approximated to the rump ; and proportionately stronger, broad, sex-serial axillary 

 tracts, which, in repose, entirely cover the enormously long wings. The length of the wings is 

 caused by the unexampled extent of the humerus and ulna. Hence also the number of remiges, 

 which amounts to fifty, is the greatest which I have ever observed in any bird. Nevertheless, 

 only ten of them are seated on the pinion, and of these the first is the longest ; the remaining forty 

 occupy the ulna in a row, and are consequently very small. These are followed on the humerus 

 by a large parapterum, consisting of about twenty feathers, corresponding with which there is 

 an equally strong hypopterurn on the lower surface. The number of rectrices is only twelve. 



1 The University collection [at Halle] also contains P. oceanica, a species very nearly allied to 

 the last-named one. In this twelve rectrices are certainly present ; in a specimen of P. pelagica I only 

 find nine, but some are wanting on the left side. BURM. 



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