44 CHELONIA. 



EMYDxV, Gray. 



Shell oval, depressed, only partly ossified, covered with soft skin, a more 

 or less broad margin remaining cartilaginous. Sternum more or less carti- 

 laginous, the ossifications proceeding from seven centres ; a broad flexible 

 flap (valve) on each side of the posterior sternal lobe. Feet broadly webbed, 

 with three strong claws anteriorly and posteriorly. 



The species of this genus of Freshwater Tiu'tles are so similar to one another, that a general 

 description will suffice to point out their principal characters. From the cartilaginous nature 

 of a portion of the shell and its consequent lightness, these animals are better adapted for a 

 sojourn in water, and the motions of their limbs and neck are much more free than in the 

 preceding genera. The ossifications become more extended over a greater portion of the 

 shell with the advancing growth of the animal, so that only a narrow margin of the upper 

 shell and about one-half of the sternum remain cartilaginous in the full-grown Turtle. 

 The ossified portions assume a coarsely granular surface in drying, and are not covered 

 with epidermal plates: only the sutures between the single vertebrae and ribs are visible. 

 The upper shell is formed by the large, oval, slightly convex vertebro-costal piece, by a 

 broad, small, elliptical nuchal piece, and by a series of marginal bones running along the 

 hinder edge of the shell. There is a pair of sternal ossifications between the fore legs, 

 another (sometimes united) between the hind legs, a third pair round the inguinal incisions, 

 and, finally, a single small ossification behind the front pair. The head and feet can 

 be entirely drawn within the shell, which is capable of some extension ; and the flexible 

 front and hind margins, together with the posterior sternal valves, serve to shut up the shell 

 completely. 



The neck is very long and flexible ; the head short, conical, terminating in a soft, flexible, 

 short tube, Avith the nasal openings at its extremity. The jaws are covered with sharp horny 

 sheaths, and overlapped by two pairs of broad, soft, pendent lips, the upper and lower lips 

 being interrupted by a broad incision in front. These soft organs of the mouth are evidently 

 the seat of a developed sense, by which these animals are enabled to search for their food, 

 which is hidden in the mud below the surface of the water. The eyes are rather small, 

 slightly directed upwards. 



Tail none. Limbs very short, covered with loose, soft skin, in which some crescentic rudi- 

 ments of scales are imbedded — four or five on the front part of the fore limb, and one on the 

 lieel of the hind foot. There are five fingers and toes, united by a very broad web ; only 

 three of them are armed with strong claws, the inner of which is a rather powerful weapon, 

 with wliich the animal can not only inflict severe wounds by scratching, but also easily 

 remove objects under which its food is hidden, or climb over water-plants, &c. 



The species of this genus are found in the East Indies, one living in Senegambia ; their 



