Prof. Reid on the Vogmarus Islandicus. 467 
the appearances just described, as observed by the aid of a com- 
mon pocket lens. 
The posterior, lateral and superior walls of the ‘cavity of the 
eranium appear to the unaided eye to be composed of fibro- 
cartilage, exhibiting no traces of a division into separate por- 
tions; and a deep groove extending between the superior mar- 
gins of the orbits, runs along the whole of the superior surface 
of the cranium, in which the elongated nasal processes of the 
intermaxillary bones are contained. The floor of the anterior 
part of this groove is occupied by the cartilaginous anterior frontal 
bones, which are raised into a well-marked ridge in the course of 
the mesial line of the cranium. The two intermaxillary bones are 
united at the mesial line and are prolonged outwards and down- 
wards along the margin of the mouth to the commissure of the 
lips. The two nasal processes of the intermaxillaries—one from 
each intermaxillary—extend backwards over the middle portion 
of the maxillary bones, along the groove on the superior surface 
of the cranium as far back as the crest of the superior occipital, 
becoming narrower as they proceed backwards. The posterior and. 
middle portions of both these processes lie in and are firmly fixed 
‘In a single groove on the superior surface of a portion of cartilage 
exceeding them in depth as well as in thickness, which also sends 
downwards a very thin ridge along the centre of a deep and wide 
groove in the anterior portion of these processes. This portion of 
cartilage is also grooved along its inferior surface and in the same 
line with that in the nasal processes of the intermaxillaries, but 
the former is considerably less deep and wide than the latter. 
These two grooves can be made to move freely upwards and 
downwards over the ridges on the upper surfaces of the maxillary 
and anterior frontal bones, and the snout can be thus protruded 
or retracted. The difference between the structure of the fibrous 
nasal processes of the intermaxillary, and that of the portion of 
cartilage firmly embracing their posterior and middle portions, 
was very well marked*. The superior maxillary bone consists 
of two distinct parts. First, a central part placed in front of the 
vomer and anterior frontals and behind the body of the inter- 
maxillary, loosely connected to the former by fibrous tissue, and 
more closely, but not sufficiently so to prevent motion between 
them, to the latter. It was in close apposition, but not immove- 
ably connected to its fellow of the opposite side, was about an inch 
and a half in length, and considerably broader at its anterior than 
at its posterior half, which was very narrow. The broadest part, 
which was a little behind the anterior extremity, was half an inch 
in breadth, and from its outer edge a broad thin plate of fibrous 
* Is this mass of cartilage the homologue of the nasal bones? 
30% 
