Some North American Turtles and Their Epizoophytic Algae

That certain algae occasionally grow on the carapaces of turtles is a fact wellknown to many persons, scientists and laymen alike; hardly a person has not heard of "mossback" turtles, and the term "mossback" has been incorporated into our language. In view of the wide familiarity with the phenomenon it is remarkable that there apparently never has been a systematic study of this interesting relationship, either on the part of the phycologists or the herpetologists. In the preparation of the present study many herpetological papers that mention epizo6phytic algae (or "moss") have been examined; only three of these (Evermann and Clark 1916; Lagler 1943; Walker, Green and Jones 1953) even give generic determinations of the algae. Neither of the two recent major works on North American turtles (Pope 1939; Carr 1952) gives this relationship more than passing remarks. Of eleven herpetological works which note the presence of algae on turtles, four involve the musk turtle, Sterno therus odorat us Latreille, seven the snapping turtle, Chelydra serpentina Linnaeus; one the painted turtle, Chrysemys picta Schneider; and one Blanding's turtle, EmMYs blandingii Holbrook (Carr 1940; Conant 1938; Lagler 1943; Pope 1939; Cahn 1937; Ruthven, Thompson and Thompson 1912; Brim-