TESTUDO NIGRITA. 
69 
irregularly subtetrahedral, narrower in front than behind. The head has an elliptical 
form, and does not rise above the level of the summit of the larger trochanter, from 
which it is sej)arated by a deep and broad cavity. The larger (a) and lesser (b) tro- 
chanters are confluent into one broad ridge, and not separated from each other by a 
smooth groove as we shall find to be the case in some of the following species. The 
length of the femur in this example is 169 millims., with a least circumference of 80 
millims. ; the width of the condyles is 66 millims. 
Of the lower leg no part needs to be mentioned particularly. The tibia is 136 
millims. long, and the fibula 123 millims. 
Also the bones of the/bo# may be passed over, with the exception of one point, viz. 
that, like some bones of the carpus, the astragalus and calcaneum are entirely coalesced, 
so that no trace of their former separation remains. 
2. TeSTUDO NIGRITA. 
No doubt can possibly be entertained as regards the correct application of this name 
to the species which I am about to describe. It had been given by Dumeril and 
BiBRON (' Erpetol. Gener.' ii. p. 80) to two examples, of which the smaller, very young 
one, is in the Paris Museum, whilst the larger, but also of young age *, is the property 
of the Royal College of Surgeons. Bibron's description is almost entirely drawn up 
from the latter specimen, which, therefore, must be regarded as the type. Howevei% I 
suspect that the very young example which Dumeril and Bibron have associated with 
this specimen should not be referred to this species, but possibly belongs to one of the 
Mascarene Tortoises. Bibron, in his description of its legs, omits all mention of the 
large scute in front of the elbow — a character which, as far as we know at present, is 
common to all Galapagos Tortoises, but is absent in the Aldabra species. Further, I 
am almost certain that the large skull described by Dr. Gray (Shield Kept. p. 6, pi. 34) 
under the name of Testudo 'planiceps belongs to the present species, for the following 
reasons: — 1. There is the circumstantial evidence that we are acquainted with the 
adult skulls of T. elefhantojyus, T. ephippium, T. abingdonii, and T. micropliyes, but 
not with that of T. nigrita. The skulls of the four former species have been preserved, 
together with their carapaces ; but the skull belonging to the shell of our single adult 
individual of T. nigrita is lost. As the skull named T. planiceps differs in a marked 
manner from all the others, we may reasonably suppose that it is that of the last-named 
species. 2. The British Museum possesses skeletons of young T. nigrita ; and although 
the skulls of these individuals have not the specific characters well developed on account 
of their young age, they show a greater resemblance, especially in its narrower snout, 
to the skull named T. planiceps than to any of the others. 
* BiBEON considered it to be an adult example ; and its relation to the Galapagos Tortoises appears to have 
escaped his notice entirely. 
