STUDIES OX THE ECTOPAIIASITIC TREMATODES OE JAPAN. X,S3 



pliasis, on the usefulness for systematic purposes of the examination 

 of the hooks "which are often present near the posterior end of the 

 body. Drawings of them made from glycerine-gelatine preparations 

 as mentioned at the beginning of the present paper would l)e of in- 

 valuable service in the identification of species. Indeed, ditferent 

 species of the same genus can be distinguished and identified with a 

 good degree of certainty by proper examination of these hooks alone. 

 When one has a new species before him and yet has not time enough 

 to make a sufiiciently minute study of it, he would do well to add 

 to its more prominent characteristics a sketch of the hooks from a 

 gl^'cerine-gelatine preparation, care being taken to bring them to 

 such a position as to enable him to get a good view of the characteris- 

 tic form — a jolj which can usually be eftected with ease by repeatedly 

 melting the imbedding medium and giving proper shifts and pressure 

 to the cover-glass. 



I. MiCROCOTYLE, P. J. V. Ijcncden et Hesse. 



This genus was first erected in 18G3 by P. J. van Bene den and Hesse with 

 the following diagnosis'); "Une partie du corps est sepan-e en arrière par an 

 étranglement et porte, des deux eûtes du corps, un très-grand nombre de petites 

 ventouses à crochets. Les œufs sont munis d'un filament aux deux pôles." These 

 writers have described five species, vi;:., M. labracis from the gill of Lahrax ltij)iis, 

 21. cantharl from the gill of Caiithanis (jriscus, M. donavani from the gill of Labnis 

 donav(i)ii, M. cnjthrini from the gill oi Pagellas cnjthrinus, and .V. cJtri/sojjhrii from the 

 gill of Chnjsojihris viihj/iris. 



In 1878 Yog t- ' described a new species, M. miifiilis, from the gill of Mur/il cej)hahis. 

 According to this writer this genus should be united with J.viiic, since "die 

 innere Organisation ist durchaus dieselbe, nur ist bei A.cine orjihii... der Yorder- 

 theil des Körpers weit mehr in die Länge gezogen und schmal, während zugleich das 



1). P. J. V. Beneden et Hesse — Recherches sur les Bdellodos et les Trematodes marins, 

 p. 112. 



2). Vogt — lieber die Forfcpflanzungsorgane einig, ectojiar. marin. Trematoden. Zeit- 

 schr. f. wiss. Zoolog., Bd. 30, Suppl., 1878. 



