CYCLEMYS ORBICULATA. 
porrecta, triangularia vel subrhomboidea: humeralia atque femoralia quadrangula, 
latere exteriore rotundato, interiore angustato : pectoralia et abdominalia magna, 
oblongo-quadrata: analia quadrangula, postice angustata: axillaria et inguinalia 
minuta, et a squamis ligamentum tegentibus parum diversa. Ligamentum quod 
sternum testee dorsali annectit, a medio scuti pectoralis usque ad marginem posteri¬ 
orem scuti abdominalis extendit, squamulis numerosis tenuibus tectum. 
Testee osseee mensura . 
unc. lin, 
Longitudo dorsi. 8 0 
Latitudo ejusdem. 7 0 
Longitudo sterni. 7 8 
Altitudo. 3 0 
In constituting the present genus upon a single character and from a single 
known species, I have been influenced by the importance of that character, as 
affording a new illustration of the relations of various forms of the family 
Emydidce. That the annectant characters which indicate the passage from the 
Testudinidas , or Land Tortoises, to the freshwater group, are to be found in the 
Box Tortoises forming the genus Terrapene , I have on more than one occasion 
endeavoured to demonstrate; and if there were a hiatus in this part of the 
series according to our former knowledge of them, it appears to me to be filled 
up by the present form, which not only bears a very obvious relation to Terra¬ 
pene in the structure of the sternum, but also, by its manifest affinity to the 
Indian forms of the genus Emys, at once shows the situation in the group 
which is naturally occupied by these, and thereby assists us greatly in deter¬ 
mining the general arrangement of the whole family. We have here an 
additional instance of the value which often attaches to the discovery of a single 
species, when such species, as in the present instance, proves to be interme¬ 
diate between two forms, the mutual relations of which would, without it, 
have at least been doubtful, if not wholly unsuspected. 
The striking similarity in the general form between this species and Emys 
spinosa , would almost lead us, on a superficial examination of the young of 
