TESTTJDO ELEPHANTIIfA. 
29 
2nd. Srd. 4th. 5th. 6th. 7th. 
millim. millira. millim. millim. miUim. millim. 
„ , ^ r Adult 70 106 105 112 120 105 
Length of centrum < 
^ I Young 37 61 57 64 69 60 
^ , ^ , . r Adult 45 48 50 53 68 78 
Depth of centrum m the middle < 
^ (.Young 29 28 29 33 46 46 
XT - ^1 -j^i. ■AA^ f ^ fAdult 25 25 27 29 53 56 
Horizontal width oi middle or centrum < 
I Young 17 16 17 18 25 30 
, ^ . , , r Adult 28 28 
Width oi anterior condyle < ,^ 
(.Young 15 16 
, , , r Adult 35 42 50 58 
Width or anterior glenoid cavity ^ ,^ 
^ ^ 1 Young 24 27 32 36 
^ . fAdult ... 31 35 44 56 
Width 01 posterior condyle < 
^ ^ \ Young ... 20 23 28 35 
, . , . (-Adult 27 68 
Width 01 posterior glenoid cavity < 
^ ^ (.Young 16 39 
Distance of outer margins of anterior zyga- r Adult 44 60 55 59 65 56 
pophyses (Young 22 34 36 37 40 35 
Distance of outer margins of posterior zyga- r Adult 52 50 48 52 48 65 
pophyses \ Young 29 32 35 36 32 45 
A comparison of this table of measurements with those given of the Galapagos 
Tortoises shows that in the much shorter vertebrae of the Aldabra species all the other 
dimensions of width, depth, or expansion of articular surfaces and processes equal or 
even exceed those of the Flat-headed group. 
Dorsal vertebrae. — The two heads of the first rib are rather broad, much divergent, 
leaving a triangular space between them and the first dorsal vertebra. The iliac bones 
abut against the pleurapophyses of the 9th, 10th, 11th, and 12th vertebrae (counting from 
the first dorsal vertebra). Their distal extremities participate more or less in the for- 
mation of the protuberance for the articulation of the ilium. I am enabled to give the 
measurements of the dorsal vertebrae of two individuals, viz. of specimens I and m of 
the list given above. 
Length of centrum of dorsal vertebrae : — 
Individual. Length of 1st. 2nd. 3rd. 4th. 5th. 6th. 7th. 8th. 9th. 10th. 11th. 12th. 
^To. carapace, mm. mm. mm. mm. mm. mm. mm. mm. mm. mm. mm. mm. 
1 31 in. 45 70 82 86 80 65 48 39 24 19 16 16 
m 291 in. 43 70 75 76 74 57 40 29 19 17 [lost] 
The number of caudal vertebrae is twenty-five, of which the last seven are coalesced 
into a single bone. The centrum of i\\e first (Plate XV. fig. A) is without haemal crest, 
and so exceedingly depressed, thin, and flat, that the anterior glenoid surface is reduced 
to a pair of small lateral tubercles, and the posterior condyle is transversely linear ; on 
the other hand, the neural arch forms an unusually thick mass of an oblongo-tetrahedral 
shape, bridging over the spinal canal, which in this part is very wide, broader than liigh. 
