78 
THE EACES OF THE GALAPAGOS. 
4. Testudo microphyes. 
This race was described by me in Phil. Trans. 1875, p. 275, from a specimen 22^ 
inches long, then lent to me by the Museum Committee of the Royal Institution of 
Liverpool, but since acquired by the Trustees of the British Museum. 
In that original description I stated that it was a fully adult male, drawing this 
inference from the concavity of its sternum — and suggested, moreover, that the speci- 
men, on account of its small size, might be the Hood's-Island race of Poetee. The 
specimens collected by Commander Cookson in North Albemarle prove at least the first 
of these views to have been erroneous, the typical specimen being undoubtedly a female. 
In this species, and perhaps also in the other flat-headed Tortoises, the sternum of the 
adult female is conspicuously concave, much more so than in males of the same size, 
though not of the same age. The concavity of the sternum of females extends over a 
greater portion of the surface of the bone than in the males (in which it is deepest 
behind the middle), and never attains the same degree of depth ; also the sides of the 
sternum and the caudal extremity never become swollen and callous. 
Commander CooKSON obtained his specimens near to Tagus Cove, about 4 miles 
inland, on a small elevated plateau covered with stunted bush and high, very coarse 
grass. Of twenty-four examples of all ages the following reached England * : — 
A. Adult male, living; carapace 33^ in. long (in a straight line); weight 240 lb. 
B. Adult male, shell, skull, and skin of legs; carapace 33|- in. long. 
C. Half-grown male, shell, skull, and skin of legs ; carapace 25 in. long. 
D. Young male, living; carapace 16^ in. long. Brought home on board the 'Chal- 
lenger.' 
E. Adult female, living; carapace 27 in. long. 
F. Adult female, living; carapace 25 J in. long. Brought home on board the ' Chal- 
lenger.' 
G. A very young specimen, living; carapace 18 in. long. 
A very great advantage has been gained by Commander Cookson bringing home 
several individuals from the same locality, thus enabling us to discriminate between 
specific characters and other modifications due to various causes. And it was impor- 
tant to ascertain that there is no variation whatever either in the three skulls from 
Albemarle Island or in those from Abingdon, and that, likewise, the carapaces from 
the same island difi"ered only in those points which I have always considered to be 
due to sex or subject to change with the progress of growth. 
As long as the Tortoises are young, growth, as far as it is externally visible, proceeds 
along the margins of all the scutes ; the sutures get broader, appearing as whitish 
seams, soft and very sensitive. After some time the young portion of the epidermis 
* The living specimens have been temporarily deposited in the Zoological Gardens ; two were put by Com- 
mander Cookson on board the ' ChaUenger.' 
