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the shields on the thorax being thin, submembranous and semitrans- 
parent, they are thick, horny and concentrically grooved like the 
shields of many other genera. It is not accompanied by the head or 
limbs of the animal, so we have not the means of determining if 
they offer any characters which, with the peculiar structure of the 
shell, might render it desirable to form it into a separate genus. 
It may be defined and thus named :— 
2. CHELODINA SULCATA. 
Shell depressed, roundish ovate, brown; shield horny, thick, 
distinctly concentrically grooved. 
Hab. Australia. 
Fam. III. Trionycip2. 
The species of this family, which have the hind legs covered with 
moveable flaps affixed to the sides of the hinder lobe of the sternum, 
named Cryptopus by MM. Dumeril and Bibron, may be divided 
into two very distinct geographic genera. 
1. Emypa, Gray. 
The margins of the upper shield strengthened with bones; the 
sternum with three pairs of callosities and a small odd one behind 
the anterior pair. Asia. 
2. CycLanostevs, Peters. 
The margin of the upper shield flexible, without any bones; the 
sternum with four pairs of callosities and an odd one behind the two 
anterior pairs; the pair on the hinder lobes small, far apart. Africa. 
It has been usually stated that the only known species of the 
genus Emypa was generally distributed over India; we have in the 
British Museum specimens only from the Valley of the Ganges. The 
young specimens all agree in the head and shell being variegated. 
We have lately received a specimen of this genus from Ceylon, 
collected by Mr. Thwaites, which differs in both the above particu- 
lars ; and in the Museum of the Society there is the shell of an adult 
animal, sent home from Ceylon by Dr. Kelaart, which shows that it 
is a most distinct species. They may be thus characterized :— 
1. EmypDA PUNCTATA. 
Back and upper part of the head pale: spotted ; the odd anterior 
callosity small, roundish triangular; the hinder callosity of adult 
ovate, inner edge semicircular ; of young triangular, far apart. 
Hab. India, Ganges. 
2, EMyDA CEYLONENSIS. 
Back and upper part of the head (in spirits) dull pale olive ; lips, 
chin and lower part of the body whitish. The odd anterior sternal 
No. CCXCVII.—ProceEpDINGs OF THE ZOOLOGICAL SOCIETY. 
