146 ILLINOIS BIOLOGICAL MONOGRAPHS [146 



are identical. In the light of the evidence the name Taenia micropteri 

 is to be considered a synonym of Taenia amhloplitis and it should be 

 stricken from the list of valid species because of the priority of the 

 latter named species. 



Eiggenbach (1896:267-268) put this species in his list of Ichthyo- 

 taenia yet he considered it a doubtful form. Under the name Taenia 

 ocellata Rud. Linton (1897) described this species from Ambloplites 

 rupestris. His data agree very well with the data of Leidy, Benedict, 

 and the writer. A difference in the length of the neck caused Linton 

 to doubt the identity of his form with Leidy 's T. amhloplitis. This 

 difference is easily explained in forms so contractile and so wrinkled as 

 these. Linton himself says, "My specimens agree with Doctor Leidy 's 

 pretty well except in the character of the neck. In T. amhloplitis the 

 neck is described as 'short or none'. In my specimens the neck is long." 

 Again in concluding Linton writes, ''This reference of these Taenia of 

 Amhloplites to the species T. ocellata is provisional only. I think, how- 

 ever, that there can be little doubt but that my specimens are identical 

 with T. amhloplitis Leidy. The apparent absence of neck in Leidy 's 

 species may be ascribed to the presence of strong transverse wrinkles, 

 due probably to the action of the preserving fluid." Benedict (1900: 

 339-355) working in Dr. H. B. Ward's laboratory redescribed this spe- 

 cies using Leidy 's specimens for comparison with material which Pro- 

 fessor Ward had collected from Micropterns dolomieu while engaged in 

 a biological investigation of Lake St. Clair in August, 1893. Benedict 

 by means of the section method demonstrated that, despite some dis- 

 crepancies in size, his specimens and Leidy 's agreed in anatomical and 

 histological details. Marshall & Gilbert (1905: 513-522) found this spe- 

 cies in Micropterns dolomieu but not in other hosts from Lake Mendota, 

 Wis. 



La Rue (1909:21 et seq.) referred to a cestode found in Microp- 

 teris salmoides as P. sp. and in a footnote on the same page (p. 21) 

 says, "This form may prove to be Proteocephalus amhloplitis Leidy, 

 which it very much resembles". That species is now known to be P. 

 amhloplitis Leidy. These specimens are referred to in the present arti- 

 cle as No. TLH947 and No. TLH1036, collected by Hankinson. La Rue 

 (1911:475) included this species in a list of species of Proteocephalus. 



The following description of this species is based partly on Bene- 

 dict's (1900) description and largely upon the writer's own work on 

 material which Professor T. L. Hankinson had sent to Professor Ward 

 for determination. This material was collected from the intestine of 

 Micropterns salmoides in the course of a biological investigation of 

 Walnut Lake, Michigan, summer of 1906. Other specimens have been 



