72 
THE EACES OF THE GALAPAGOS. 
(Plates XLIII. and XLIV. fig. D, a). 4. A very deep hollow on the lower surface of 
the occipital, in front of the condyle (b)*. 6. On the front margin of the temporal 
fossa, corresponding to the suture between parietal and tympanic, immediately in front 
of the foramen carotidis externse, there is a large, prominent, flat, rough tuberosity (c) 
for the insertion of a portion of the temporal muscle ; a broad, not very deep groove (d) 
separates this tuberosity from the zygomatic arch. 6. Tympanic cavity exceedingly 
large, especially its posterior portion, the entrance being somewhat narrowed by the 
groove just mentioned ; the outer tympanic rim is a regular circle, with a shallow notch 
in its hinder circumference for the passage of the Eustachian tube. 7. This notch is 
very remote from the columellar foramen ; and a sharp ridge runs the whole distance 
from the notch to the foramen, serving as a rest for the auditory ossicle. 8. The front 
margin of the intermaxillaries projects beyond that of the frontals, but much less so 
than in the Aldabra Tortoises ; so that the nasal opening, although still obliquely sloping 
downwards, is scarcely higher than broad. 9. The inner nostrils are advanced, not very 
distant from the end of the snout, and on the palatal view of the skull are nearly 
entirely hidden below the alveolar lamella of the maxillaries. 10. The intermaxillaries 
are short, not quite one half of the length of the maxillaries ; and their foremost portion 
is deeply hollowed out below, and vertically bent downwards to form the truncated 
beak. The suture between the intermaxillary and vomer is immediately behind the 
inner angle of the alveolar edges of the maxillaries. 11. Palatal region much less 
concave than in T. elephantina, and provided with a rather high median longitudinal 
crest; posteriorly it is bordered on each side by the raised pterygoid edge, which is 
obtuse in its anterior, and trenchant in its posterior half. The distance between the 
foramina palatina is much less than their distance from the anterior extremity of the 
vomer. 12. Anterior surface of the tympanic pedicle deeply excavated. 13. Lower 
jaw with a double alveolar ridge, the symphysial portion being simply vertical, without 
a backward dilatation of the lower margin of the bone. The opposite surfaces of the 
angular and coronoid are closely approximate, leaving only a narrow cleft between 
them. Upper margin of the angular moderately excised. 
The skull of a young example, 2 j;^^- inches long, shows some of the characteristics 
described in the adult skull, viz. the greater depth and the less width of the palatal 
region, the deep hollow in front of the tympanic pedicle, and the conformation of the 
anterior half of the tympanic cavity. The groove between the temporal tubercle and 
zygomatic arch, as well as the hollow in front of the occipital condyle, are clearly indi- 
cated. On the other hand, the tympanic pedicles are less distant from each other than 
in the adult, the mastoido-tym panic process is only slightly produced backwards, and 
the occipital crest is short and much less prominent' — points of difference which can be 
accounted for by the young age of the individual. 
* In the figure given by Dr. Geat the artist has entirely omitted to express the depth of this hollow 
by shading. 
