216 



s. GOTO. 



thi/imus and describecl by him under the name of Puli/stoma tlnjuni. Later it 

 was described under the name of Fohjstoma duplicata by Rudolphi'^ in his 

 "Entozoorum synopsis." The diagnosis ^^ given by Blain ville is as fol- 

 lows : " Corps ovale, déprime, continu ou non articulé, compose de deux parties ; 

 une antérieure, bien plus petite, subcylindrique, ridée ; l'autre postérieure, beaucoup 

 plus grande, ovale, alongee, déprimée et bordée inferieurcment par trois paires de 

 ventouses, armées à l'intérieur de deux petits crochets opposes. Tête petite, peu 

 distincte, portant la bouche à son extrémité. Anus dorsal à la jonction du cou et du 

 corps. Orifice des organes de la gént'ration au même endroit en dessous." The 

 *' anus " above referred to is probably the opening of the vagina, which is very con- 

 spicuous on a surface view. In his " Histoire naturelle des Helminthes " D u j a r d i n^-* 

 gives the following diagnosis of the species, for which he adopts the name given it by 

 Rudolplii : " Corps grisâtre, mou et lisse, long de 12 à IG mm., large de 3.4 mm., et 

 elliptique au milieu, rétréci en avant, élargi en arriére, ou se trouvent les six 

 ventouses rangées transversalement, avec deux papilles intermédiaires ; — bouche 

 terminale ; — ventouses bivalves, soutenues par plusieurs pieces cornées qui, en 

 se rapprocliant les font paraître divisées fdiij>Ucat(iJ,'' a description differing only 

 in a few points from that of ]^>lain ville, but in many respects more incomplete. 

 Die sing') in his " Systema helminthum" erected for the species a new genus 

 Plagiopclth, with the following diagnosis : " Corpus elongatum depressum. Caput 

 corpori continuum. Os Acetabula ventralia octo in corporis parte dilatata mar- 

 ginalia, série simplici disposita, elliptica planiuscula, marginata, singula acetabulum 

 transverse ellipticum margine involutum, centrali minus, includentia. Genitalia 



externa Porus excretorius Piscium marinorum ectoparasita." A new 



addition to our knowledge of the genus contained in the above is the correct ascer- 

 tainment of the number of posterior suckers (eight), the innermost pair of Avhich is 



]). Rndolphi — Entozoorum synopsis, 1819. pp. 125 & 438. Cited on the authority of 

 Dujardin, Diesin<^, and Braun. 



2). Blainville— Dictionnaire des sciences naturelles. T. 57, 1828. p. 570. PI. XXVII, fig. 1. 

 Cited on Braun's authority. 



3). Dujardin — Histoire naturelle des heloiiuthes, 1815. p. 318. 



4). Diesing — Systema helminthum, i).416. The diagnosis given in his " Revision der 

 Myzheluiinthen " (p. 3G8) seems to me scarcely an improvement. 



