128 'Journal of Comparative Neurology and Psychology. 



ing order: Chrysemys marginata, Aspidonectes spinifer, Chelydra 

 serpentina, Aromochelys odorata, Nannemys guttata, and Terra- 

 pene Carolina. The first five species were sufficiently abundant 

 for purposes of habit study and it is with these only that I deal in 

 this paper. The first on the list, Aspidonectes spinifer, was found 

 to be the most interesting and instructive, and its habits are here 

 described as fully as observations permit. The other species 

 studied will be dealt with more briefly, attention being directed 

 chiefly to the diff^erences in behavior displayed by the various 

 forms. In brief, the treatment will be comparative. 



CLASSIFIED ACTIVITIES. 



I. Aspidonectes spinifer (the Common Soft-Shelled Tortoise of 

 our Lakes and Rivers). 



This species is, in many respects, the most highly organized 

 and specialized of our tortoises. In point of intelligence, alert- 

 ness, swiftness on land and in the water, and in general capability 

 it ranks first of the species studied. A classified account of the 

 activities of this species will serve to lead up to a general conception 

 of its disposition and character. 



Seasonal Activities. — These tortoises are first seen early m 

 April and seem to be in a very weak condition after their winter's 

 dormancy. I have frequently picked them up from the sandy 

 beaches where they lay with head, neck and legs extended to the 

 full, apparently stupified by their first exposure to the sun's 

 warmth. At these times it is an easy matter to walk up and 

 capture them, for when seized they make only a feeble effort to 

 escape. A coating of mud on limbs and carapace is circumstan- 

 tial evidence that they have wintered in the mud on the lake 

 bottom. It is possible that only much weakened specimens find 

 it necessary to craw4 out on shore for a preliminary warming up. 

 After the first few warm days in April they are no longer to be 

 seen basking on the sand, but seem to devote themselves to very 

 active feeding. Mating must take place during April or May but 

 I have not had an opportunity to observe it. 



Aspidonectes nests rather later than the other species, as a rule 

 not earlier than the middle of June. Nesting continues until the 

 middle of July, and in rare cases considerably later. 



As the water becomes colder in late fall they are less often' seen 



