Eastern Box Turtle Parasites 89 



in the small intestines, which is substantially more than found in 

 previous studies. The number of worms per turtle was substantial 

 with a mean (and range) of 62.2 (1-295) for males, 22.5(1-93) for 

 females, and 27.5 (1-80) for juvenile turtles. We do not know why 

 the mean number of this trematode is so much higher in North Carolina 

 box turtles than that reported from other localities or other species of 

 turtles. 



Krull (1935, 1936) reported that Pseudosuccinea columella (Say) 

 became infected after eating trematode eggs (experimental infection) 

 and began to shed xiphidiocercariae within 28-32 days. Cercariae success- 

 fully penetrated and encysted as metacercariae in three snail species: 

 P. columella, Helisoma trivolvis (Say), and Lymnaea traskii (Lea). 

 Krull postulated that turtles were infected during the spring and early 

 summer when they ate snails in semi-flooded flats. He also noted 

 that metacercariae were never abundant, although snails had been 

 repeatedly exposed to thousands of cercariae. However, he did report 

 that one snail would occasionally acquire a much heavier infection 

 than others in the same group perhaps because they began feeding 

 more quickly than others. In light of more recent studies on host 

 immunity, genetic susceptibility might be a more reasonable cause 

 than a behavioral trait. In either case, these "super-infected" snails 

 will influence the range of worms in infected definitive hosts. 



Nematoda 



Oswaldocruzia sp. — Seven species of Oswaldocruzia have been 

 described from North American amphibians and reptiles (Baker 1977): 

 O. subauricularis Travassos, 1917; O. leidyi Travassos, 1917; O. pipiens 

 Walton, 1929; O. collaris Walton, 1929; O. waltoni Ingles, 1936; O. 

 euryceae Reiber, Byrd, and Parker, 1940; and O. minuta Walton, 

 1941. Oswaldocruzia subauricularis is a neotropical species and has 

 only been reported once in the United States. Baker (1977) redescribed 

 O. pipiens and regarded O. collaris and O. eurycea as synonyms of 

 O. pipiens. He also treated O. waltoni and O. minuta as species 

 inquirendae and O. leidyi as a nomen nudum. Accounts of develop- 

 mental and transmission patterns in Oswaldocruzia vary widely. Baer 

 (1952) stated that O. fillicollis (Goeze) (presumably referring to 

 Oswaldocruzia filiformis [Goeze, 1782] from amphibians molted twice 

 within the egg and was thus infective when the egg was consumed. 

 Baer also noted that L 3 larvae might sometimes hatch and remain 

 ensheathed in the preceding molt until consumed. Baker (1978a) reported 

 that eggs from frogs and toads were laid in the 16-cell stage, and L } 

 larvae hatched within 24 hours of passage in the host's feces. Laboratory 

 cultured specimens developed to the ensheathed, infective L 3 stage 

 within 3-4 days at room temperature. Anuran infection occurs via 



