202 



S. GOTO. 



pavaslta." Although in these diagnoses the only point of difference of some generic 

 importance observed by the author seems to have been the pediculate condition of 

 the posterior suckers of the one in contradistinction to those of the other, yet most 

 of the species known to Diesing and placed by him respectively in the two genera 

 are precisely those which, though I have not been able to study them personally, 

 still judging from the descriptions of others, I should bring just under those two 

 genera in which they are respectively included by him. Thus there can be no doubt 

 on the one hand that 0. scombri fKuhiiJ, one of the two species described by 

 Diesing, is to be included in this genus as I have characterised it below. On the 

 other hand, DicUdojihora Merlamji (KulinJ is, to judge from its (incomplete) descrip- 

 tions given by Die ckhoff, ') in all probability to be included under Diclidojihom 

 as defined below, while as to D. palmata (Leuclc.J there can be no doubt, from the 

 general form of its body, of its belonging to the same genus. As to OctocoUjle lan- 

 ceolata (F. S. Leticlc.J there is no doubt from its descriptions given by Dieckhoff^^ 

 that it is to be brought under another genus, the most salient point of difference 

 being the presence of a dorsal vagina. I have, however, adopted Diesing's 

 nomenclature, as he seems to be the first who has recognised the difference of the 

 two genera under question. P. J.v.Beneden and Hesse also have noticed this 

 difference and included them under two genera, Octocotyle and Pterocotyle ; the latter 

 being co-extensive with our DicUdophora, as may be seen from the following diag- 

 nosis given by the authors : " Huit ventouses portees sur de longs pedoncules 

 unis a la base terminent le corps en arriere. Le ver est regulierement efiS.le en 

 avant, large vers le milieu et retreci vers I'origine des ventouses. La bouche est 

 flanquee de deux ventouses et une couronne de crochets entoure I'orifice des organes 

 sexuels." Like Diesing these authors regarded the unimportant pedicels of the 

 posterior suckers as of generic value ; but their idea is capable of a surer foundation, 

 as may be seen from the diagnoses of the two genera given below. 



The name Octostoma was proposed by Kuhn in 1829; but like most writers 



sin^luin quadrivalve, valvulis semiciroularibus, membranaceis, limbo comeo cinctis, asser- 



culatis, in cardine traDSverso mobilibus. Androgyna ; apertura genitalis masoula feminea 



antrorsuin sita, uncinulorum corona simplici cincta. Poras excretorius Tractus iu- 



testinalis bicruris, coecus. — Ovipara, ovulis utraque extremitate appendice filiforme crasso. — 

 Piscium marinoruin ectoparasitLi." The penis is evidently mistaken for the female genital 

 opening. 



1). Dieckhoff— t c. p. 263. 



2). Dieckhoff— Z. c. p. 253. 



