GYPOGERANUS. 63 



short, half sparsely feathered, posteriorly densely feathered. Eyelids with small lashes. Nostril 

 with a central process, as in the Noble Falcons. 



2. F. degencr ILLIG. Beak with the nostrils and cheeks exactly as Jin the preceding 

 species, but the pterylosis somewhat stronger in all parts, and the spinal tract different, having a 

 remarkably short fork, with its limbs broad and strongly divergent. The posterior portion reaches 

 this fork with its most anterior sparse feathers. Remiges of the specimen examined not present 

 in their full number ; first four graduated, the first as long as the seventh, the second longer 

 than the sixth ; the third and fourth equal in length, and the longest ; the fifth but little shorter ; 

 the first three with a slight emargination of the inner vane. 



3. F. cheriway seu brasilieiisis (ViEiLL., Gal., I, PI. 7). This species is distinguished by 

 the remarkable depth of its beak and the oblique position of its elongated nostrils. The ptery- 

 losis also, although closely agreeing with that of F. degener, differs in having the dorsal portion 

 of the spinal tract elliptically dilated upon the caudal pit, where it encloses a narrow, lanceolate, 

 insular space a structure which I have never met with elsewhere among the Falcons. Remiges 

 of the specimen examined imperfect ; the first five with a diminution of the inner vane, the third 

 and fourth the longest. 



6. GYPOGERANUS. 



i 



The remarkable bird known as the Secretary (F. serpentarius GMEL.), which constitutes the 

 sole representative of this group, appears to me, from its general structure, to approach most closely 

 to the subgenera Morplinus and Polyborus, and to be essentially only an exaggerated form of the 

 long-legged type which is proper to most of the members of these groups. Moreover, the entirely 

 shielded tarsus is by no means a character peculiar to it, as it is already indicated in F. antliracinw 

 LICHT., which, except as regards the differences in the pterylosis, is very nearly allied to F. uru- 

 bitinga. Gypogeranus is, however, pterylographically peculiar in many respects, especially in the 

 connection of the two gular stems of the inferior tract as far as the point where the inner branch 

 issues from them. This is present, but very narrow. The outer branch, on the contrary, is much 

 broader, perhaps twice as broad as the main stem ; it is, at the same time, quite free, and far 

 removed from the stem. The latter descends very close to the crest of the sternum, and only 

 turns a little more outward upon the ventral region, where it terminates at a considerable distance 

 from the anus. The cervical portion of the spinal tract, in which the two rows of large nape- 

 feathers are situated, is broad and densely feathered; its branches between the shoulders are 

 short, but broad. The ^dorsal portion commences at the fork, with two parallel rows of single 

 feathers, and proceeds in the same form to the caudal pit, where it becomes broader, but is 

 imperfectly defined and sparsely feathered at the sides. The lumbar tracts are present, and 

 biserial, but not long. In the wings I counted twenty-eight remarkably acute remiges, of which 

 the first is equal to the seventh and the second to the sixth ; the third, fourth, and fifth are the 

 longest, and nearly equal ; the fourth slightly exceeding the other two. The first five show a 

 diminution of the inner vane, which extends very far downwards ; in repose they reach about to 

 the middle of the tail. The rectrices are graduated and acute, with the two middle ones obtuse, 

 and suddenly becoming much longer. The naked lores, cheeks, and eyelids are certainly not 



