The depressed, soft-margined carapace of softshells has been mentioned as an adaptation to facilitate burrowing in soft sand or mud, and more suited for concealment than for speed in aquatic locomotion (Carr, 1952:429; Smith, 1956:162). Nielsen (1951:264-65), commented that in various lotic invertebrates, dorsoventral flattening of the body was no commoner than in lentic invertebrates; he wrote that a dorsoventral flattening is a disadvantage to an animal in a strong current and is an adaptation "probably ... not to withstand the current directly, but to avoid it by seeking shelter in narrow crevices." Probably another aid to concealment, mentioned by Williams and McDowell (1952:272), is the plastral hinge. Concealment of softshells is not enhanced by growths of algae on the carapace. Proctor (1958:637-38) reported that the common, epizoöphytic alga of chelonians, _Basicladia_, has never been reported from _Trionyx_; the same author recorded a large amount of filamentous algae, principally _Stigeoclonium_, but the algae could be easily wiped from the turtle, and Vinyard (1955:64) recorded an alga, _Dermatophyton radians_, attached to the skin of the legs of _Trionyx_. I noted a small patch of greenish scum growing near the insertion of the neck on a softshell (_spinifer_ from Lake Texoma); cursory examination by Dr. R. H. Thompson, disclosed one of the colonial ciliate protozoans (resembling _Opercularia_) with enmeshed green or blue-green algae. Evermann and Clark (1920:592) mention a _spinifer_ from Lake Maxinkuckee, Indiana, having a growth of _Opercularia_, covering the plastron. _Movement_