4 PROCEEDINGS OF THE NATIONAL MUSEUM vol.81 



terial, while Stunkard gives only one measurement, 116/^., for both 

 P. megacofyle and P. inicrocotyle. Stunkard lists, as the distinguish- 

 ing characters between P. megacotyle and P. inicrocotyle^ the number 

 of hooks in the genital coronet, and the size of the caudal suckers. 



For P. megacotyle he gives 36 and 42 as the number of hooks in 

 the genital coronet of the two specimens counted. For P. microcotyle 

 he gives 32. In my material the number varies from 29 to 37. Stunk- 

 ard does not give the size of the caudal sucker of P. megacotyle^ but 

 by measuring the figure we arrive at 0.4 mm as the probable diameter 

 of the caudal suckers. The diameter of the caudal suckers of P. 

 micfrocotyle is given as 0.28 mm. The diameter of the caudal suckers 

 in my material varies from 0.3 to 0.45 mm. The range of variation 

 in my material is so great that specific distinction between P. Tiiega- 

 cotyle and P. microcotyle seems unlikely. This seems even more un- 

 likely when Stunkard's limited material is taken into consideration. 



Family HERONIMIDAE WARD, 1918 



Genus H'ERONIMUS MacCallum, 1902 



This genus is known only from the lungs of North American 

 turtles. 



HERONIMUS CHELYDRAE MacCallum. 1902 



Since MacCallum described this worm it has been reported from 

 many hosts other than Chelydra serpentina. At Houston, Tex., it 

 has been found in the lungs of Kinosternon subrubrum hippocrepis 

 and of Pseudemys elegans. Only the former host is new. 



Family SPIRORCHIDAE Stunkard, 1921 



Subfamily Spirorchinae Stunkard, 1921 



Genus HENOTOSOMA Stunkard, 1922 



This genus was established in 1922 by Stunkard for Spirorehis 

 chelydrae MacCallum and Henotosoma haem/ito'bium, Stunkard. 

 MacCallum (1926) rejected it, but neglected to say why. Although 

 undoubtedly closely related to Spirorchie, it seems to be worthy of 

 recognition as a distinct genus, with characters as defined by 

 Stunkard (1923). 



HENOTOSOMA CHELYDRAE (MacCallum, 1922) 



Four specimens of this fluke were taken from the heart of a snap- 

 ping turtle captured near Houston, Tex. Comparison of my speci- 

 mens with the descriptions of E. tiaematohiuni Stunkard and of 

 H. chelydrae MacCallum left me in some doubt as to which of the 



