STUDIES OX THE ECTOPARASITIC TREMxlTODES OF JAPAX. 99 p, 



0. emimjimtUiJ wore clescribo.l by Olsson'^; antl finally in 1890 a fourtli species 

 (O. Prenanti) was added to the genus by St.-Remy-\ Besides these there is 

 according to Diesing^) another species not yet described but mentioned by Wage- 

 ner in a note to a paper of his pubhslied in " Naturk. Yerhaud, Harlem, XIII," 

 as living on the gill of Scijumus (liimsi. This species is not mentioned either by 

 Braun or St. -Be my, and I am not sure whether it will prove to be identical 

 with some one of the species already described, or to belong to quite another genus. 



The original diagnosis of Diesing is as follows; "Corpus lineari-lancoolatnm 

 depressura, utrinque angustatum. Caput corpore continuum. Os subtcrminale. 

 Acetabula sex disco elliptico oxtremitati caudali supra adnato, biseriatim immersa, 

 hemisphaerica, margine uncino simplici inferna adnato apice libero armata. 



Aperturao genitales Porus excretorins in apice caudali. — Piscium marhiorum 



ectoparasita." This was improved in his "Bevision"*> as follows: "Corpus 

 lineare-lanceolatum depressum, (ippcndiculo caudali postico. Caput corpore con- 

 tinuum. Os subtcrminale. Acetabula sex, lamellae ellipticae, extremitati corporis 

 posticae subtus adnatae, biseriatim immersa, hemisphaerica, margine uncino simplici 

 inferne adnato, apice libero, armata. Androgyna ; aperturae genitales postpositae 

 ventrales antrorsum sitae, medianae ; penis vaginatus ante aperturam fcminoam 

 situs. Pori excretorii duo in appendice caudali, terminales. — ^Tractus intestinalis 

 bicruris, coeeus. — Ovipara ovulis utraque extremitate appendiculo filiformi in- 

 structis. — Piscium marinorum ectoparasita " — a diagnosis which has been repeated 

 in its essential points by subsequent writers, but which requires some modifications 

 in accordance with the facts already mentioned in the anatomical part of the 

 present paper. It has moreover been stated that in some species the caudal append- 

 age does not bear any hooks near its extremity. This statement sounds somewhat 

 anomalous to me ; but as I am not able to reexamine the species in question, I shall 

 leave the statement as it stands, and give the generic diagnosis as follows : 



Body elongated, very thick, narrow towards both 

 ends; anterior end l)liint, and with a snb-elJipsoidal sucker 



1). Olsson — Biclrag til Scandiaaviens helminthfauna. K^-1. svenska vetensk. Acad. Handl. 

 X. F. XIV, 187S. p. 35. Cited on the authority of Branu and St.- Remy. 



2). St.-Remy — Sur une espèce nouvelle do Polystomien du geni-e Onchocotyle Dies. Rev. 

 biol. d. Xord de la France. III. ann., 1890. p. 41. Cited on the combined authority of Braun 

 and St.-Remy. 



3). Diesing— Revision der Myzhelminthen, 18ÔS, p. 371. 

 4). Diesing— Revision, p. 370. The italics are mine. 



