SWIMMING BIRDS. 139 



16. Thinocorus rumicivorus, ESCHSCH., Zool. Att. (Ocypetes torquatus, WAGL., Isis, 1829, 

 p. 762). This remarkable bird, which Wagler very improperly compares with the Sand Grouse 

 (Pterodes), (is in every particular an aberrant Scolopacine form, related to Glareola in exactly the 

 same way as Chionis to Hcematopus, or Dramas to Recurvirostra. BuRM.). 1 Its pterylosis differs 

 from the form represented for Charadrius only as follows : the outer branch of the inferior tract 

 is more closely approximated to the main stem, and lies exactly upon the middle of the breast ; 

 the ventral portion of the same tract is very strongly arched, and dilated externally ; the hinder 

 part of the dorsal tract has its longitudinal space extending further down, is rather wider on the 

 whole, and comes in contact anteriorly with the fork of the anterior part ; the inferior space 

 extends up beyond the middle of the neck ; and, lastly, the axillary tracts, as in Tachydromus, are 

 broadly rounded and united anteriorly with the inferior tract. In the wing, which is nearly as 

 long and pointed as in Glareola, I counted twenty-six remiges ; the somewhat cuneate tail 

 consists of twelve feathers. 



17. Glareola. In both species of this genus I found exactly the same pterylosis as in 

 Thinocorus and Tachydromus ; the nurnbetfof remiges is also the same, as is that of the rectrices, 

 although the tail is very remarkable for its furcate form. However, I could discover no down- 

 feathers among the contour-feathers in G. orientalis ; hence the outer branch of the inferior 

 tract appeared to be somewhat broader, and to be rather more connected with the main stem 

 anteriorly. 



CHAPTER VIII. 



SWIMMING BIRDS NATATORE8. 



THE most general pterylographic character of this last main division of the class of Birds 

 consists in the very broad form of their tracts, with which is combined a comparatively narrow 

 form of the spaces. Nevertheless, the arrangement of the plumage approaches much less to an 

 uninterrupted feathery covering than in other broad-tracted birds, especially in those Picarite in 

 which, as in the Maccaws, Hornbills, and Colics, there is nearly aptilosis continua ; because in the 

 Natatores the contour-feathers stand remarkably close together, and form such dense tracts that 

 even a very narrow space may be distinctly recognised. In the tracts, moreover, the contour- 

 feathers are inserted perfectly regularly in parallel rows, which are always placed obliquely to the 

 longitudinal axis of the body, and meet, on the margins of the perpendicular median plane 

 which would divide the body into two symmetrical halves, in such a manner as to form an acute 

 angle, when they are not separated by a space situated at that part. This oblique direction of 



1 Nitzsch- was inclined to refer it to the Alectorides a view which is admissible inasmuch as the 

 Alectorides themselves are only aberrant forms, which belong partly to the Scolopacirue (Otis), partly 

 to the Fulicarice (Dicholophus, Grits, Psophia, and Palamedea). BURM. 



