1882.] ON THE ANATOMY OF ERETHIZON DORSATUS. 271 
the-possession of powder-down patches, in the oil-gland being nude 
(?Mesites),and in the interruption of the dorsal tract in the neighbour- 
hood of the scapulz. Pterylographically, therefore, there is no special 
reason to unite these forms with the Rails. Judging from M. Milne- 
Edwards’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 particular, the fact of Mesites being schi- 
zorhinal is a strong point in view of its relationship being, along with 
Rhinochetus and its allies, to the Pluvialine group, where I have 
already? placed it. In spite of M. Milne-Edwards’s remarks’, I 
see no reason for doubting the value of the schizorhinal character of 
the nasal bones as a mark of the genetic affinities of birds, especially 
when, as in the present case, other facts point in the same direction. 
I should be inclined therefore to consider (1) that Mesites, 
Eurypyga, and Rhinochetus have all sprung from some common 
ancestor, which must have been a generalized Pluvialine form pro- 
vided with powder-down tracts; (2) that of the forms which this 
common stock gave rise to, all have become extinct save the three 
in question, which, having become isolated in three widely separated 
localities, have each acquired certain special characters not found in 
the others; (3) that, judging at least from the pterylosis, the 
Malagash Mesites is perhaps more nearly related to the New-Cale- 
donian Rhinochetus than to the Neotropical Zurypyga. 
5. Notes on the Anatomy of Hrethizon dorsatus. 
By Sz.-Gzorcre Mivarr. 
[Received February 16, 1882.] 
Having had an opportunity, through the kindness of Dr. Giinther, 
of examining a spirit-specimen of Hrethizon dorsatus, the following 
points have appeared to me possibly of some interest. 
The tongue is long and narrow, its extreme length being 4!"7 and 
its greatest breadth (at its hindmost end) being 1!'-4; close to the tip 
it is only *5 (cent.)*. Its hinder margin has a deep median notch. The 
intermolar eminence is considerable. There is no median groove on 
the dorsal surface ; and there are but two oval and rather large cir- 
cumvallate papille at the hinder margin of the tongue. The long 
axes of these two papille diverge forwards and outwards. The sur- 
face of the dorsum of the tongue is, for its anterior half, covered 
1 This, 1881, p. 4, and P, Z. 8. 1881, p. 644. 
2 The greater or lesser size of the beak will zo¢ account for the schizorhinal 
or holorhinal character of the nares, as suggested by M. Milne-Edwards. Else 
why should the big-billed Platalce, Ibises, Didumeulus, Laride, Alcide, be all 
schizorhinal, whilst the slender-billed Rails, Colymbide, and such Tubinares as 
Puffinus and Procellaria, to say nothing of such forms as the Meropide, Dendro- 
colaptide, and Nectariniide, are all equally holorhinal? Nor can Iadmit with 
M, Milne-Edwards that the Preroclide are related to the Gallina, or the Lbidide 
to Tantalus, there being plenty of collateral evidence to prove the reverse. Hence 
any argument based on such assumed affinities also fails. 
In this paper all the measurements are in centimetres, except where other- 
wise expressed. 
