136 'Jourj^al of Comparative Neurology and Psychology. 



water an inch or less in depth and partially covered with sand or 

 mud. Their protective coloration was so perfect that only the 

 keenest scrutiny could detect their presence. This protective 

 measure is quite a necessary one, as a young Aspidonectes would 

 furnish a tender morsel for fish or other tortoises, if it were at all 

 conspicuous. This I found to my dismay when I tried to keep 

 several young Aspidonectes in an aquarium with adult Armo- 

 chelys and Chrysemys. 



Summary. — The following brief diagnosis of the character or 

 disposition of Aspidonectes may now be attempted: 



The adults are characterized by remarkable swiftness, alertness, 

 wariness and fearlessness when in natural conditions. 



In captivity they are sullen in the extreme and show marked 

 depression of spirit. 



The young acquire gradually the characteristics of the adult. 



2. Graptemys geographica (the Map Tortoise). 



Of the three species of the family Emydidae, that occur in Lake 

 Maxinkuckee, Graptemys geographica is the most markedly 

 aquatic, never wandering about on land except during the nesting 

 season. Owing to the abundance of this species and its easily 

 observed activities it seems best to introduce a study of its habits 

 in this place instead of following the order of systematic affinities. 



Seasonal Activities. — Graptemys appears earlier in the season 

 than any of the other species studied, a few specimens coming to 

 view as early as the tenth of April. They are first seen basking 

 on the banks of the lagoons, where the water warms up many 

 days earlier than in the open lake. On first emerging from the 

 water they are so thickly coated with mud that they are apt to be 

 mistaken for stones. 



At this time they are less wary than usual and may be captured 

 with a dip-net, if a cautious approach be made. A week or so later, 

 however, they become so sensitive to terrestrial vibrations that, 

 even if one takes every precaution to remain in concealment, it is 

 almost impossible to approach nearer than some fifty feet, without 

 causing them to take alarm. 



During the month of April they spend all the sunny portion of 

 the day basking in the sun, but on the approach of warm weather 

 they leave the lagoons in large numbers, presumably in search of 



