— 132 — 



longicaudata, as seen in fig. 18 of Meyer's work, is consi- 

 derably narrower than tlie dilatation of tiie oesophagus, whe- 

 reas in our parasite the intestine is on the contrary mucli 

 wider than the bulb. I consider the abovenamed data sufficient 

 for establishing the specific independence of the parasite 

 Oxyiiris myriapodicola. It is, however, beyond doubt that 

 the future investigator will have to unite the species 0. lon- 

 gicaudata Meyer 1896, Thelastomum labiatum Leidy 1850, .0. 

 myriapodicola mihi and, probably, 0. jjacliyjidi into one com- 

 mon genus, and place as a generic diagnosis both the structure 

 of the mouth, and the organization of the genital organs of 

 the male. 



The absence of males prevents me from fulfilling this in 

 the present paper. 



14. Oxyuris leidyi nov. spec. 



This parasite was found together with 0. myriapodicola 

 in the intestine of Polydesmus sp. 



Contrary to the buccal organs of 0. myriapodicola which 

 resemble those of Thelastomum labiatum Leidy 1850 so clo- 

 sely, although in other items of its structure differing sharply 

 from 0. myriapodicola, — our new parasite, 0. leidyi n. sp., 

 has quite a different structure of the mouth as compared 

 with Thelastomiwi labiatum, being in the rest so similar to 

 the latter, that for a long time I could not decide to separate 

 it into an independent species. 



Males are unknown. 



The females have a spindle-shaped body, provided with 

 a very long, elastic, flagellated caudal process, the length of 

 which is but slightly less than half the size of the entire 

 body-length. The cuticle is deeply striated transversely pro- 

 ducing the characteristic annulate aspect. The length of body 

 of the female reaches 2,465 mm. at a maximum width= 

 0,255 mm. On the sides of the body are situated the alate 

 dilatations of the cuticle which commence on the level of the 

 collar of the oesophagus (i. e. the point where the cylindrical 

 portion of the oesophagus passes into the bulb) and extend 

 to the base of the caudal process. The structure of the buc- 

 cal organs of this parasite— for the study of which I was 

 compelled to apply oil immersion — is so peculiar and intere- 

 sting that I will describe it in' fuller detail (see. fig. 38). 



