60 PROCEEDINGS OP THE NATIONAL MUSEUM vol. 81 



respectively, from the anterior end. The vulva is 1.4 to 1.6 mm from 

 the anterior end. From it the vagina runs posteriorly for about 1.3^ 

 mm, where it divides into the two convergent uteri. The egg-filled 

 uteri occupy the middle third of the body. Following the uteri are 

 two elongate sacs, the seminal receptacles, which are about 0.5 mm 

 long and 0.11 mm wide. The ovaries lie coiled in the body, caudal 

 to the seminal receptacles. The eggs measure 23/x by 38/x. The fe- 

 male tail is blunt and only 0.11 to 0.13 mm long. 



Host. — Leiolopisnia laterale. 



Habitat. — Stomach. 



Locality. — Houston, Tex. 



Type specimen.— \].'^:^^l. Helm. Coll. No. 31712. 



Remarks. — Two immature specimens of Thubunaea taken from the 

 stomach of Acris gryllus may belong to this species. They possess 

 a short vestibule, three teeth on the lips, and a cephalic collarette 

 as the above species does, but, as the sexual organs have not yet be- 

 gun to develop, it is impossible to be sure of their identity. 



This species is easily separated from Thubunaea pud'ica and T, 

 parkeri by the well-cutinized spicules and the cephalic collarette. 



Family CAMALLANIDAE Railliet and Henry, 1915 



Genus CAMALLANUS Railliet and Henry, 1915 



This genus is represented in North America by several species that 

 are parasitic in fishes and turtles. For our purpose only those para- 

 sitic in the latter hosts need be considered. Several species have 

 been erected by Leidy, Magath, and MacCallum for these forms, but 

 in the present state of our knowledge it seems best to include them all 

 under one species. 



CAMALLANUS TRISPINOSUS (Leidy, 1851) 



Synonym: Camallanus americanus Magath, 1918. 



A number of nematodes taken from turtles are tentatively referred 

 to this species. The hosts are Chelydra serpentina, Kinosternon 

 subi'uhrum hlppocrepis.^ Pseudemys elegans., Deirochelys reticib- 

 laria ( ?), and Amy da ferox (?) from Houston, Tex. ; and Chrysemys 

 picta from Newfane, N. Y. The worms from Deirochelys reticularia 

 are all females, and those from Amyda ferox are immature, and 

 therefore these two records must be regarded as doubtful. Among 

 the worms of my material there seems to be a variation in the length 

 of the spicules that is associated with the host. These spicule meas- 

 urements are given in Table 2. 



Table 2 shows that in length of spicules my parasites fall closer to 

 Camallanus americanus Magath than to G. trispinosus Leidy. Wal- 



I 



