208 ILLINOIS BIOLOGICAL MONOGRAPHS [208 



head is smaller, its testes are more numerous and the position of its 

 genital pore is very different from that of 0. filaroides. 0. perspicua 

 differs from 0. lonnbergii (Fuhrmann) from Nccturus maculosus Raf. 

 in having a smaller head and smaller suckers and more numerous testes. 



OPHIOTAENIA LACTEA (Leidy) Sp. Inq. 



1855: Taenia lactea Leidy 1855:443 



1911 : Ophiotaenia lactea La Rue 1911 :481 



On account of the inaccessibility of Leidy 's description, it is here 

 quoted in full : 



"Taenia lactea Leidy. — Head small, continuous with the neck, without ros- 

 tellum ; acetabula anterior, hemispherical, situated at the four angles. Neck mod- 

 erately long. Segments anteriorly transversely oblong, posteriorly longer than the 

 breadth, square with rounded angles. Generative apertures marginal (indistinct 

 in the specimen.) 



"HAB. — One specimen 16 inches long and % of a line wide was found in 

 the intestine of Tropidonotus sipedon. In alcohol the specimen contracted one- 

 half the original length and widened to i line." 



La Rue (1911:481) made this a species inquirenda in his newly 

 established genus Ophiotaenia. This is probably a species of Ophiotae- 

 nia and may be the same as the species reported by the writer from 

 Natrix rhombifer. Unfortunately the writer has had as yet no oppor- 

 tunity to make a study of any Ophiotaenia from Natrix sipedon and 

 hence is unable to form an opinion of the likelihood that the two species 

 of host harbor the same parasites. Leidy 's description is too inadequate 

 to permit a careful determination of the position of his form and since 

 his specimens could not be had by the writer for study his species is 

 considered to be a species inquirenda. Further research may indicate 

 its proper position. 



