EMYSMEGACEPHALA. 53 



is continued backwards, between the orbits, and terminates at the occiput; two 

 other Hnes of the same size and colour begin behind the orbits on each side, and 

 are continued along the superior surface of the neck; at the distance of a fourth of 

 an inch at the back of each orbit, is a greenish-yellow blotch; the inferior surface 

 of the neck is dark green, and marked with yellowish lines; one of these begins at 

 the chin, and soon subdivides, the branches running towards the articulation of the 

 lower jaw, whence it is continued along the neck. Beginning where the latter 

 line subdivides, is another longitudinal and larger line, running along the middle 

 of the throat; on each side of these principal lines are many others, both on the 

 cheek and throat; near the angle of the mouth is a remarkable yellow blotch, 

 surrounded by yellowish concentric lines; another blotch is found in front of the 

 tympanum, whence it descends, terminating in a hne that runs along the lateral 

 and inferior borders of the neck. 



The anterior extremities are coloured like the neck, with two or three longi- 

 tudinal lines of dirty yellow. The general colour of the posterior extremities is 

 like the anterior, with transverse bands of dirty yellow. The superior surface of 

 the leg and foot are dark green; the inferior surface is of the same colour, marked 

 with blotches and longitudinal lines of greenish-yellow. The tail is greenish-brown, 

 marked with longitudinal lines of dingy yellow; these hnes are distinctly marked 

 only as far as the vent. 



Dimensions. Length of shell, 8i inches; of sternum, 7 inches; height, 3 inches; 

 breadth of shell, 6 inches; length of tail, 2} inches; length beyond the vent, li 

 inches. 



Geographical Distribution. This animal has been observed by Prof. Troost 

 in the Cumberland river, and other western waters. The specimen from which 

 the accompanying drawing was taken, was found by him in the neighbourhood of 

 Nashville, Tennessee. 



Habits. The E. megacephala is bolder and more active than the animals of 



