STUDIES OX THE ECTOPARASITIC TREMATODES OF JAPAN. 901 



Hahitat — Gill of Authias Scldcgclii (Jap. Akasngi). 



Lo ca lit]! — Mi sak i . 



Drt ft'— December 188!). 



in. OcTOCoTYLE, Diesing. 



This and the following genus DicUdojihom have been combined by most 

 writers under the name of Octohotltrltiin. The latter name is due to F. S. 

 Leuckart^' whose original diagnosis runs: "Corpus elongato, depresso, piano ; 

 apertura oris antica, infera, simplice ; in utroque partis corporis posticae latere 

 acetabula suctoria quator." He, however, included in it at least two groups of 

 forms which are, in my opinion, to be separated from each other and placed 

 in distinct genera. So f\ir as I have been able to make out with a somewhat 

 scanty access to the literature of the subject, especially the older, Diesing is the 

 first writer who has made this distinction and erected two genera, which respectively 

 include those forms which are, in my opinion, to be brought under at least t\Y0 

 distinct genera. One of these has been named by him Octocoti/le, the diagnosis 

 of which he gives as follows-) : " Corpus elongatum depressum. Caput corpore con- 

 tinuum. Os terminale. Acetabula in postico corporis margine uncinis duobus sub- 

 basilaribus interjectis utrin(|ue quator, prominula orbicularia inermia (?) et duo 

 parellela infra os sita. Apertura genitalis feminea elliptica uncinulorum corona 



simplici cincta. Penis Porus excretorius Piscium marinorum 



ectoparasita." The other of his gênerais DidiJojihora, the original diagnosis ^^ of 

 which ran : " Corpus subovale v. sublanceolatum depressum. Caput corpore con- 

 tinuum. Os subterminale. Acetabula in margine caudali octo, solitaria, valvulis 

 4 membranaceis asserculatis, in cardine transverso mobilibus, longe pedicellatis. 

 Apertura genitalis Porus excretorius Piscium marinorum ecto- 



1). F. S. Leuckart — Versuch einer naturgemässen Eintheilung der Helininthem nebst 

 deui Entwurf einer Verwandtschafts- und Stufenfolge der Thiere überhaupt. Heidelberg, 

 1827. I make the above quotation on the authority of Braun (Würmer, p. 534). 



2). Diesing— Systema helminthum, vol. I, 1850. pp. 417 & 421. 



3). This was slightly improved in his " Revision der Myzhelminthen " (p. 383) as follows : 

 " Corpus subovale v. sublanceolatum depressum. Caput collo continuum, subtus acetabulis 

 duobus juxtapositis. Os subterminale. Plectana octo pedicellata in postico corporis margine. 



