278 
DR. A. GUNTHER ON GIGANTIC LAND-TORTOISES. 
The measurements of the two specimens are as follows : — 
Length of carapace. Width of carapace. Depth Sternum. Caudal plate. 
In str. line. Over cnrv. In str. line. Over curv. of carap. Length. Width. Length. Width. 
Spec. inches. inches. inches. inches. inches. inches, inches, inches, inches. 
Ad. <5 38 41£ 25 42 16 25£ 24 4£ 6| 
Young ... 121 i4i 9 141 51 1Q1 8£ 1£ 2} 
Skull. — The skull * is 4-| inches long, measured from the front margin of the inter- 
maxillary to the occipital condyle, and 4 inches broad in its widest part, between the 
zygomatic arches ; therefore it is comparatively larger than that of T. ephippium. The 
sutures between the various bones can still be traced ; and from the condition of the rest 
of the skeleton it is evident that growth had not entirely ceased in this specimen. The 
skull is extremely similar to that of T. ephippium ; so that the skulls alone, without the 
evidence gained from other parts of the skeleton, would hardly afford sufficient grounds 
for specific separation. The points in which the two skulls differ are the following 
only: — (6) The outer tympanic rim of T. vicina (Plate 41. fig. A) has a subcircular 
outline, and (7) the ridge which runs from the Eustachian notch ( e ) to the stapedial 
foramen, and to which the columella is attached, is high and rather sharp. (13) The 
impression in front of the tympanic pedicle is much deeper than in T. ephippium. 
The skull of our young example is only 2 inches long, and agrees in every respect 
with the adult, except that the parietal crest is less compressed and the tympanic case 
less produced backwards, as in all skulls of the young of these Tortoises. 
Cervical vertebras. — On comparing the neck-vertebrae of T. vicina with those of T. 
elephant opus, we find them generally to be somewhat less slender, and with the crests 
and ridges less developed ; otherwise they are formed according to the same type, and 
the first, seventh, and eighth are the only vertebrae which exhibit peculiarities indi- 
cative of specific distinctness. In the atlas (Plate 40. fig. B) the lateral portion of the 
neural arch is but little constricted, at least as wide as the broad zygapophysis, which 
is longer than that part of the bone which forms the roof of the neural arch. In the 
seventh vertebra (Plate 41 . fig. C) the summit (a) of the neural crest is not single as 
in the other species, but split into two prominences, separated from each other by a 
deep notch. In the eighth vertebra the haemal crest is produced forward to the level 
of the anterior articulary surface, and almost hamate in form, whilst it does not extend 
beyond the middle third of the length of the centrum in T. elephantopus. 
* A reduced figure of this skull is given iu Huxley’s ‘ Elementary Atlas of Comparative Osteology,’ pi. 3, 
but, owing to the elementary object of that work, the details of the specific characters to which attention is 
drawn in this paper are not sufficiently well expressed ; indeed it would be impossible to render some of them 
conspicuous in a figure reduced in size. 
