14 



43. Oxyuris evoluta, Linstow (Path. Hist., 1636), from the 

 small intestine of a Canada porcupine, Erethizon dorsatus 

 (P. Z. G. Lab., 991). Linstow (Mith. Mus. Berlin, \, heft 2, 

 p. 20) has described from Hystrix brachyura ( ?) an oxyuris 

 apparently the same as the specimens here recorded; but so 

 far as is known to the writer the present instance is the only 

 one, aside from Linstow's original observation, in which 

 these parasites have been recognized, and inasmuch as Lin- 

 stow's record is extremely brief the description entered in 

 the laboratory records from the material in hand seems worthy 

 of full publication. Linstow found his material in the 

 zoological collection of the Berlin Museum of Natural History 

 labelled as obtained from Hystrix brachyura, but in a foot- 

 note to his communication manifests uncertainty as to the 

 correctness of the specific name of the porcupine. He states 

 in brief that only female examples were present, which 

 measured 9.1 mm. in length and 0.47 mm. in thickness; that 

 the esophagus, which ends in a bulb, measured 1 : 11.5, and 

 the long pointed tail 1 : 7.7 of the body length of the worm; 

 that the vagina of the specimens projected as a thick tube 

 0.22 mm. in length and 0.044 mm. thick; and that the cuticle 

 at the head end was swollen out in a fusiform manner. 



The notes of laboratory study (Plate I) of the writer's 

 material, made July 22, 1907, are as follows: From the small 

 intestine of this animal (Canada porcupine) were obtained 

 fifteen small nematodes, all female and non-gravid, the 

 largest (Fig. 1) measuring 8 mm. in length and 0.5 mm. in 

 thickness at thickest level (about 2 mm. from head end), 

 the smallest about half this size. Specimens nearly round in 

 section; tapering anteriorly to the head, which at base of lips 

 measures from 0.07 to 0.09 mm. in diameter; tapering more 

 gradually posteriorly to a long slender tail ending almost 

 effilate, as in oxyuris. Cuticle thin and transparent, finely 

 striated transversely (striae 0.01 mm.); at head end two cuti- 

 cular swellings (Figs. 2 and 3) of small size one on either side of 

 base of dorsal lip; and back of lips cuticle of head end slightly 

 swollen in fusiform manner. The body wall, from about the 



