TESTTJDO ELEPHANTINA. 
27 
the tympanic condyles (outside measure). 2. The upper surface of the parietals is a 
flat triangle, the outer edges of which converge towards, and finally are merged into 
the tetrahedral occipital crest, which is of moderate length. 3. The tympanic case with 
the mastoid is not produced backwards ; so that the posterior margin of the paroccipital 
is but little excised. 4. The groove on the lower surface of the occipital, in front of 
the condyle, is very shallow; no styloid process on each side of the condyle. 5. The 
prominent tuberosity on the front margin of the temporal fossa, which in some of the 
Galapagos Tortoises is so much developed, is but feebly indicated. 6 *. The tympanic 
cavity is of moderate extent, the outer tympanic rim having an irregular outline, 
like that of an inverted human concha, the convexity being anterior. In its 
posterior margin there is a very deep triangular excision for the passage of the 
Eustachian tube. 7. This excision is so deep that it nearly extends to that part of 
the bottom of the cavity Avhich is pierced by the foramen for the columella ; 
this ossicle, therefore, does not rest on a trenchant ridge as in the Galapagos 
Tortoises. 8. The front margin of the intermaxillaries projects so much beyond 
that of the frontals, that the nasal opening slopes obliquely downwards and is much 
higher than broad. 9. The inner nostrils are situated far back, and, on the palatal 
view of the skull, may be seen free and uncovered by the alveolar lamellee of the maxil- 
laries. 10. The intermaxillaries are long, about two thirds the length of the maxillaries ; 
and their foremost portion is neither very concave nor much bent downwards to form 
the beak. The suture between the intermaxillary and vomer is at a considerable dis- 
tance behind the inner angle of the alveolar edges of the maxillaries. 11. The whole 
of the palatal region is deeply concave, with a very low median crest along its bottom. 
The triangular space of which the foramina palatina and the anterior extremity of the 
vomer form the points is isosceles. 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 description of the other parts of the skeleton is taken principally from the 
adult male specimen c and from I, a male not fully grown, with a carapace 31 inches 
long. 
The cervical portion of the vertebral column is comparatively much shorter than that 
of the Galapagos or Rodriguez Tortoises ; the several vertebrae are shorter and thicker ; 
the crests are lower, without additional lateral crests ; the majority of the posterior 
articulary processes have a strongly divergent outward direction, the notches between 
them being very wide and deep ; and the anterior are nearly perpendicular to the 
* It is very singular that although the osseous parts of the auditory organ are so well developed, nevertheless, 
according to the unanimous testimony of observers, these Tortoises are absolutely deaf. I find this con- 
firmed so far in my young living example, that it never takes notice of the noisy approach of a person whom it 
cannot see, nor is it disturbed by the fall of a stone behind its back. Perhaps the faculty of hearing, although 
never acute, is not entirely lost until the individuals have attained to a great age. 
E 2 
