334 ON THE PTERYLOSIS OF MESITES. 



trated patches of Mesites may easily be derived from the more diffused 

 arrangement found in Rhinocketus * and Eurypyga. 



A full account of the pterylosis of Rhinochetus is still a desideratum, 

 Dr. Murie having unfortunately omitted any account of the syste- 

 matically more-important contour-feather tracts in his account of the 

 " dermal structures " of the Kagu (L c.). 



I have at present insufficient material to describe these thoroughly, 

 though an examination of two imperfectly-feathered specimens in spirit 

 demonstrates considerable agreement between the Kagu and Mesites. Of 

 Eurypyga we likewise have but imperfect information, due to Nitzsch f, 

 and not to my mind very satisfactory, judging from the material before me. 



In Rhinochetus, as in Mesites, the neck-feathering is quadriserial, though 

 the median dorsal space is much narrower below and the lateral neck- 

 spaces very broad ; the two dorsal tracts terminate close together about 

 the level of the anterior end of the scapulae, and are quite separate from 

 the posterior portion, which is only forked to a slight extent anteriorly, 

 and widely dilated mesially. These differences seem to be due mainly to 

 the greater development of the dorsal powder-down tracts of Rhinochetus, 

 these covering most of the dorsal aspect of the trunk, except a narrow 

 median space along the backbone and a reversed heart-shaped area on the 

 pelvis, to which spaces therefore the contour-feathers are nearly confined. 



Below, as in Mesites, the inferior tract of each side is nearly or quite 

 broken up into two by the interruption of a patch of powder-down 

 feathers ; and the pectoral branch is likewise quite separated from the 

 main tract, as in no other bird known to me except Mesites, powder-downs 

 also intervening between the two. The humeral tract is quite free from 

 the inferior one. On the other hand, in the number of its rectrices (16), 

 and the absence of an aftershaft to the feathers, Mesites differs from 

 Eurypyga and Rhinochetus, both of which have 12 rectrices i and an 

 aftershaft. The number of primaries in all is 10. 



Mesites, Rhinochetus, and Eurypyga agree together, but differ from the 

 P.Z.S. 1882, Rallidae, in having well-developed and strong rectrices, in the possession 

 p. 271. Q f powder-down patches, in the oil-gland being nude (? Mesites), and in 

 the interruption of the dorsal tract in the neighbourhood of the scapulsD. 

 Pterylographically, therefore, there is no special reason to unite these 

 forms with the Rails. Judging from M. Milne-Ed wards 's account and 

 figures of the osteology of Mesites, numerous differences between these 

 two forms also exist in the osseous parts of their structure. In parti- 

 cular, the fact of Mesites being schizorhinal is a strong point in view of 

 its relationship being, along with Rhinochetus and its allies, to the Plu- 



* Cf. Murie, Trans. Z. S. vii. pi. 56. figs. 1-3. 



t ' Pterylography,' Eay Soc. ed. p. 129, pi. viii. fig. 15. 



J Rhinochetus has not 10, as erroneously stated by Murie, loc. cit. p. 468. 



