Seemingly there is little difference between species in preference of nesting sites; a sandy substrate is probably preferred. Gravid females of _ferox_ and _spinifer_ may wander overland some distance and select places where the view of the water is obstructed by vegetation; both species may wander little and nest in full view of the water. Concerning _muticus_, it is of interest that of the many nests discovered by Anderson (_loc. cit._) on an open sandbar, all were those of _muticus_ and none was a nest of _spinifer_. The nests of _muticus_ mentioned by Muller (_loc. cit._) and Goldsmith (_loc. cit._) were on open sandbars. On June 4, 1953, six clutches of eggs were found on an open sandbar of the Escambia River, Florida; all hatchlings from those eggs that were successfully incubated were _muticus_. On June 1, 1954, three nests were found on an open sandbar of the same river (Pl. 50); the temperature within the nests at 6:30 a. m. was approximately 25° C. Two nests were dug in a sand substrate on the level portion of the bar (Pl. 51, Fig. 1). The third clutch of eggs was deposited in a sand-gravel substrate at the brim of the incline from the shore (approximately 30 degrees and about five feet above the water); the eggs of this clutch were arranged rather symmetrically (Pl. 51, Fig. 2). Unfortunately, most of the eggs from these three clutches failed to hatch. Although the data are far from conclusive, I have the impression that _muticus_ limits its sites of egg deposition to the open regions of sand bars and does not lay inland where it must traverse vegetated areas unless preferred nesting sites are submerged or otherwise unsatisfactory. Females of _spinifer_ may utilize open sandbars for deposition of eggs but not areas where _muticus_ occurs. In areas where both _muticus_ and _spinifer_ occur, the latter probably lays farther inland or on the landward margins of sandbars.