1G7 



Carapace feebly serrated posteriorly. Nuchal narrow, its hinder border 

 notched. Carapace rounded bebiai ia. the females, more pointed in the 

 males. Plastron with its posterior lobe about two-thirds the width of the 

 carapace; distinctly notched behind. Bridge wide, rising little toward 

 the carapace. Limbs well developed, scaly, the digits well provided 

 with webs. None of the claws of the male much elongated. Head of 

 the males small, that of the females large. Snout not at all projecting. 

 Upper jaw with the cutting edge smooth, somewhat sinuated, not notched 

 in front; the alveolar surface very broad, united with its fellow back 

 nearly to the choanse. Lower jaw flat, its alveolar surface resembling 

 that of the upper jaw. The jaw not hooked at the tip. 



Ground-color of the carapace dark olive. Over all the scutes there is 

 a network of greenish lines, so that each of the large scutes is divided 

 into about 8 to 10 areas. Under side of the marginals with sutural spots 

 of dark green, which enclose irregular lines of yellow. Head, neck, 

 limbs and tail dark green, almost black, with numerous lines and streaks 

 of greenish yellow. Behind the eye is a somewhat triangular spot of 

 greenish yellow, often elongated backward. Plastron yellow, with the 

 sutures of the scutes marked with a dark line. Occupying the center of 

 the plastron is a large lyriform blotch of brown, which looks as if the 

 color had almost faded out. 



The size of this species averages larger than that of M. pseudo-geograph- 

 ica, full grown specimens being about 10 inches long. It may become 

 still larger. 



This species is distributed from Pennsylvania and New York to Michi- 

 gan and A rkansas. It is found no doubt in all the streams and lakes of 

 Indiana. Known localities are New Harmony ; Brookville ; North Man- 

 chester, Wabash county (A. B. Ulrey) ; Lake Maxinkuckee ; Eel and 

 St. Joe rivers; Terre Haute (Blatchley); Fall Creek, Marion county 

 (W. P. Hay) ; Kankakee River at English Lake ; Tippecanoe River at 

 Winemac. 



This turtle can be readily distinguished from any other species occurring 

 in Indiana by the extremely expanded masticatory surface of the jaws. 

 From M. pseudo-geographica it may be distinguished by the reduced keel, 

 especially of the large females, the rudimentary tubercles of the keel, 

 and especially by the triangular spot behind the eye. As stated in the 

 description of M. pseudo-geogr-aphica, it is the head of the female that is 

 large; that of the male is little, if any, larger than males of the same 

 size of pseudogengraphica. My observation is that the females are usually 

 much larger than are the males. Dissections made of 7 specimens taken at 

 Lake Maxinkuckee showed that 4 were females, all with carapace more 

 than 6 inches long ; the others were not over 4 inches long, and all were 

 males. I think that males may become somewhat larger than these, but 

 not nearly so large as the largest females. 



