270 MR. FORBES ON THE PTERYLOSIS OF MESITES. [Feb. 21, 



The third ^a.tch is inferior in position, lying just at the commence- 

 ment of the pectoral region, between the two halves of the inferior 

 tract internally and the anterior extremity of their separated pec- 

 toral branch externally. 



The fourth patch is longer and narrower than its fellows, lying on 

 the ventral region just outside the middle part of the inferior tract. 



The Jifth (lateral) patch lies more or less transversely, in the 

 neighbourhood of the axilla, between the posterior ends of the outer 

 pectoral and humeral tracts. 



No Ardeine bird has any such lateral pair of patches ; and only 

 Cancroma has the anterior dorsal pair. These moreover lie outside, 

 and not inside, the dorsal tracts in that bird. On the other hand, 

 the concentrated patches of Mesites may easily be derived from the 

 more diffused arrangement found in Rhinochetus ^ and Eurypyga. 



A full account of the pterylosis of Rhinochetus is still a 

 desideratum, Dr. Murie having unfortunately omitted any account 

 of the systematically more-important contour-feather tracts in his 

 account of the " dermal structures " of the Kagu (/. 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", 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 (lb), and the absence of an aftershaft to 

 the feathers, Mesites differs from Eurypyga and Rhinochetus, both 

 of which have 12 rectrices^ and an aftershaft. The number of 

 primaries in all is 1 0. 



Mesites, Rhinochetus, and Eurypyga agree together, but differ 

 from the Rallidce, in having well-developed and strong rectrices, in 



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



^ ' Pterylography,' Eay Soe. ed. p. 129, pi. viii. fig. 15. 



s Bhinochetus has uot 10, as erroneously stated by Murie, loc. cit. p. 468. 



