113] PROTEOCEPHALIDAE—LA RUE 113 



summary of the hosts which had been recorded for this species up to 

 this time. Rudolphi (1819:495) stated that Bremser's specimens which 

 had been taken in the pyloric caeca of Salmo thymallus belonged to 

 Taenia longicollis and not to Bothriocephalus. He further stated that 

 Taenia Renkina Schrank is identical with Taenia longicollis because 

 Salmo Wartmanni is called Renken in central Germany. Schrank 's 

 (1803:242) description of Taenia renkina is not at hand hence it is 

 necessary to follow Rudolphi 's judgment in the matter. Dujardin 

 (1845:585) added but little to the data of the earlier authors. Diesing 

 (1850:512-13) gave a literature review that is of value. Von Linstow 

 (1878:262) in his catalogue of entozoa gave Salmo salvelinus as a host 

 of this species. 



Zschokke (1884:11, 14-16) identified and described some cestodes 

 from Coregonus fera and Salmo umbla, Lake Geneva, as Taenia longi- 

 collis. A careful comparison of his descriptions of T. longicollis and T. 

 ocellata, likewise reported by him from the same hosts, causes the writer 

 to conclude that his specimens belonged to the same species. Length 

 forms the chief difference between his species. In describing certain 

 organs of the two forms he used almost identical phrases. Kraemer 

 (1892) in his study of Taenia ocellata evidently used length as the chief 

 distinguishing character. Zschokke 's description of T. longicollis does 

 not agree with the description and figures of that form as given by von 

 Linstow (1891:565-576). Von Linstow 's specimens were taken from 

 Coregonus eperlanus, one of the hosts in which Rudolphi found T. lon- 

 gicollis. It is therefore probable that von Linstow 's specimens rather 

 than Zschokke 's belong to Rudolphi 's species. Moreover, von Linstow 's 

 description agrees more completely with Rudolphi 's than does Zschok- 

 ke 's. Lonnberg (1894:803) included Taenia longicollis Rud. in the list 

 of species in his genus Ichthyotaenia. 



Zschokke (1896:772-777) listed Ichthyotaenia longicollis only in 

 Trutta fario from Lake Geneva. Thanks to Prof. H. B. Ward, the 

 writer has been able to examine parts of a strobila of Zschokke 's "T. 

 longicollis aus Forelle" (Trutta fario) and is able to state positively 

 that it is not the same species as von Linstow 's T. longicollis. Nor is it 

 the same as the specimens from Coregonus fera which Zschokke sent to 

 Professor Ward as T. ocellata (No. 0.99 in Prof. H. B. Ward's collec- 

 tion, the type of P. fallax La Rue). Von Ratz (1897:159) listed Ich- 

 thyotaenia longicollis from Esox lucius from Lake Balaton in Hungary. 

 This is probably a misdetermination. Von Ratz gave no description so 

 not even a probable determination can be made. Miihling (1898:36) 

 reported Ichthyotaenia longicollis Rud. from Coregonus albula at Nico- 

 laiken and from Osmcrus eperlanus at Rositten in East Prussia. He 



