334 Miscellaneous. 
in fact, does not resemble that of its modern relative. The parvetals 
are narrow and compressed ; the frontals expand into a broad well- 
rounded snout. We cannot ascertain from our specimens whether 
the nasals bore protuberances for the support of horns. It seems 
probable that they did not. 
This animal will be fully described and figured in a later publi- 
cation. The above is intended merely as a preliminary notice. 
Orthocynodon may be briefly described as an Eocene perissodactyle 
Ungulate with the premolar-molar dentition of a. rhinoceros, and 
somewhat resembling Amynodon in the possession of canines and loss 
of the median incisors. It has little of the rhinocerotic character in 
the skull; but the resemblances in the dentition point it out as re- 
lated to Amynodon, with which it belongs, among the group of 
Kocene progenitors of the Rhinocerotide. 
Measwremenits. 
Total length of molar series of the lower jaw........ "192 
Antero-posterior diameter of the first lower molar .. °038 
Transverse diameter of the first lower molar ......., 022 
Vertical diameter of the crown of the canine........ ‘040 
Transverse diameter of the first upper molar..,..... 035 
Antero-posterior diameter of the first upper molar .. *035 
Total length of the upper molars, estimated ........ 165 
Amer. Journ. Sci., Sept. 1882, p. 223. 
On the Structure of the Head of Archeopteryx. By W. Damss. 
In the examination of the Archcopterysx in the possession of the 
Berlin Royal Mineralogical Museum, the results of which will be 
published in detail with figures, the matrix previously concealing 
some parts of the skeleton has been removed; and this has given a 
clear insight into the structure of the head. 
When the specimen was obtained for the Museum, two large aper- 
tures were seen on the exposed right side of the skull; the 
hinder one, situated beneath the roof of the skull, was easily recog- 
nized as the orbit, especially as it contained a well-preserved bony 
sclerotic ring, consisting of separate plates lying one over the other, 
asin so many living birds. The anterior margin of this orbit is 
formed by a narrow bone, which is turned a little backward and ex- 
tends down to the base of the skull. This bone (the lacrymal) at 
the same time forms the posterior boundary of a second, large, 
rounded triangular aperture, in the middle of which there is a 
crushed piece of bone separated from its natural connexions with 
the other parts of the skull. This aperture-has been interpreted 
as the nasal aperture by authors, as by C. Vogt* and O. C. Marsh*t. 
It appears, however, that the anterior part of the skull was still 
concealed by matrix ; and it was only by very careful removal of the 
latter that the contours of the skull were completely exposed. This 
gave the important result that in front of the supposed nasal aper- 
ture there is a third aperture, placed obliquely to the longitudinal 
* Rev. Scient. 2° sér. xvii. 1879, p. 242. 
+ British Association Report, York Meeting, 1881. 
