18/2.] DR. J. ANDERSON ON MANOURIA AND SCAI'IA. 133 



sternum (fig. 7, p. 137) had the pectoral plates separated from each 

 other by the interval of only 2 inches, while in the other and shorter 

 individual the same plates did not approach each other by 4" 5'" 

 (fig. 8, p. 137). In the typical example of T. phayrei, ou the other 

 hand, the pectoral plates formed a suture of 1" 4'" (fig. 5, p. 136). 



The next facts in connexion with these shells, which are otherwise 

 identical, are these, that those which have the pectoral plates apart 

 have concave, while those which have them forming a suture have flat 

 sterna — two facts which are full of significance. 



Keeping in mind the intimate connexion that subsists between the 

 faunas of Assam, Cachar, and Arakan, and being impressed with the 

 foregoing facts, I asked the assistance of Capt. Butler at Luma- 

 jooting, in the Naja hills, to the east of the Brahmaputra, in procuring 

 certain rather large Land-Tortoises, which he had informed me were 

 found in his district. I forwarded to him drawings of the sterna of 

 M . emys and T. phayrei ; and in return he sent me three living Tor- 

 toises and two perfect shells, four of the specimens having flat, and 

 one a concave sternum. The thoraces of all these individuals in no 

 way differ from the thoraces of my first specimens ; and the four 

 with flat sterna are true T. phayrei, and the individual with the con- 

 cave sternum has the separated pectorals of M. emys. Capt. Butler's 

 specimens are all from one locality in Assam, to where I had antici- 

 pated it was likely T. phayrei would extend. Having thus proved 

 that T. phayrei and M. emys are associated together in Assam, in 

 the same localities, aud keeping in view the facts that the animals 

 are apparently identical, that the thoraces in no way differ from each 

 other, that the pectoral plates of individuals referable to M. emys 

 present variations in their size, and so approximate to each other as 

 to lead directly into T. phayrei, and that the same plates in individuals 

 which would be referred to this species may either have a broad or 

 very narrow suture, the conclusion is forced upon me that the two 

 so-called species are one and the same — Testudo emys, Miiller, — and 

 for the cogent reason that, beyond the variation of the pectorals, 

 they present no other points of difference. From the circumstance 

 that all the specimens having flat sterna, and therefore probably 

 females, have the pectorals more or less united, while, on the other 

 hand, the individuals with concave sterna, and therefore those which 

 I suppose to be males, have these plates varying in their degrees of 

 approximation, I am inclined to regard the first form of pectorals as, 

 to a certain extent, distinctive of the female, and the second as cha- 

 racteristic of the male Testudo emys, Midler. There is, however, an 

 element of uncertainty whether or not these two types of pectoral 

 plates are exclusively sexual, because, as the Manouria type varies 

 from widely apart to approximated pectorals, and the T. phayrei 

 type from a broad to a very narrow pectoral suture, it is possible, 

 nay probable, that further and other modifications may be brought 

 to light. But the specimens before me indicate only two tvpes of 

 variation (one characteristic of the flat, and the other of the concave 

 sterna) — the former being a suture of variable intensity in the middle 

 line, the second a pectoral plate of variable development between the 



