Dr. J. E. Gray on the Box Tortoises. 105 
This makes six species of Calliste now known to inhabit Central 
America and the Isthmus of Panama, viz. C. larvata from the hot 
forest-region of the Atlantic side of Guatemala, C. Francesce* from 
Costa Rica and Veragua, C. Dowii from Costa Rica, C. Frantzii from 
the same country, C. gyroloides, a species ranging from Costa Rica 
to Bolivia, and C. znornata from Panama to the Isthmus of Darien. 
The single specimen of this Calliste now described was procured 
by Capt. J. M. Dow, Corr. Mem. Z.S., at San José, the capital of 
Costa Rica, during a short visit he paid to that city in the early 
part of the present year, and by him most kindly presented to me. 
He was unable to inform me exactly whence it came ; but it was most 
probably obtained from the low forest-region of the Atlantic slope. 
I dedicate the species to Capt. Dow, whose researches in the ma- 
rine fauna of Central America are too well known for me to need to 
dilate upon the justice of the appellation. 
OBSERVATIONS ON THE Box TORTOISES, WITH THE DEscCRIP- 
TIONS OF THREE New Asiatic Species. By Dr. J. E. 
Gray, F.R.S., etc. 
The knowledge of the animals of our own country is progressive 
and only gradually acquired ; and how much more so must it be as 
regards the species which we receive from a distant country, whence 
we get only isolated specimens, and often in a more or less imperfect 
condition, without any account of how they live, and what they eat, 
and in what manner they conduct themselves ! 
In such cases how can we do more than guess at what is a species, 
and into what groups the species should be divided? and yet, because 
we doubt in what we are doing (and the older we become in the 
study, the more do we see the necessity for doubting, and the more 
do we see the imperfection of our materials)—yet, on the doubts 
which arise from such causes and not from any want of faith in the 
principle that species are permanent, if we only had materials enough 
to study them properly, do theorists wish to support the theory that 
species gradually pass into each other, and have been derived, or 
rather have originated, from such transformations. Never was a 
theory more baseless, as far as our knowledge is concerned. 
This imperfection of our knowledge is specially the case with re- 
spect to exotic Tortoises, of which we sometimes only procure the shell, 
at other times the animal with the shell in a more or less perfect 
condition ; and when the latter is procured, we find that the conclu- 
sions that we had come to as regards the probable form of the animal, 
or some part of it, are more or less incorrect, and we are thus obliged 
to reconsider the situation the species occupies in the series. 
* T had considerable doubts whether this species was really separable from 
C. larvata, but, having examined a number of skins of both species, have come 
to the conclusion that the distinction, small as it is, is constant. Dr. Sclater 
has pointed out in his ‘ Monograph’ what the differences are, to which I may 
add that C. Francesce seems a lighter rather than a brighter bird than C. larvata; 
the blue on the forehead is a trifle broader in the former ; and the outer bluish- 
green margin to the middle wing-coverts of the latter is almost obsolete in the 
former. In fact, there is just a difference, and that is all. 
