Siiufeldt on the Osteology of Cinclus Mexicanus. 215 
The external form of the brain-case is more or less globular, 
the supra-occipital prominence being well developed behind. 
Above in the median line a shallow furrow is carried forward as 
far as the fronto-maxillary suture. 
There- is but little of interest to note in the lower mandible, to 
illustrate the points we have in view. 
From this slight sketch of this part of the skeleton we are pre- 
pared to look a little into how Cinclus compares with other 
forms of near kin. The writer, to illustrate his remarks, offers 
the student the four accompanying cuts of the superior aspects of 
the skulls of birds chosen with the view of showing the compar- 
able points. 
A is of Oreoscoptes montanus , B of Stall a mexicana , C of 
Cinclus itself, and D of Siurus ncevius. 
In the figures, the angle formed at /, h , and b ] is due to the 
lachrymal bone on that side ; viewed from above in such forms as 
Si alia, Turdus grayi , Oreoscoptes , Hylocichla unalascce , and 
no doubt Merula and Mint us , less so in Harpor kynchus , this 
projection is markedly angular; while in Siurus , the Wrens, and 
rather less so in Anthus , it is rounded , as shown in Siurus and 
also in Cinclus itself. 
Of the forms we have examined, Siurus appears to be closer 
to the Dipper in this respect than any other genus, the Wrens 
( Salpinctes ) next, and Anthus next. This also applies to the 
manner in which the median furrow at the summit of the cra- 
nium approaches the fronto-maxillary suture, also shown in C 
