234 s. GOTO. 



Hluterende mit den Saugnapfen nosli etwas scliiefer ziir Acbse des K5rpers stelit als 

 bei den typiscben Microeotylen." In the same year Lorenz') described anotber 

 species, M. mormyri, from the gill of Fagellus mormyrus, and shed mucb light on its 

 anatomy and histology. 



Parona and Perugia^) have recently (1889 & 1890) described four additional 

 species, vh., M. sanji from the gill of Sargiis Bondeletii, S. annularis, and S. vuUjaris, 

 M. alcedinis from the gill of Smavis alceclo and Miena vulyaris, M. tracldni from the 

 gill of Tiacliimis radlatiis, and M. saljxie from the gill of Box saljM. Thes6 writers 

 have also minutely redescribed all the preexisting species and added a valuable con- 

 tribution to our knowledge of the general anatomy of the genus. Finally in 1891 

 S n s i n o ^) described a new species.from the gill of Umbiina ciirhosct, and named it 

 M. Panceiii. 



It has already been mentioned above that according to Vogt this genus should 

 not be separated from Axine. Lorenz, on the other hand, decidedly maintains its 

 separation as a distinct genus. The distinctive characteristics are according to him 

 (1) that Microcotyle is perfectly symmetrical in external form, the symmetry showing 

 itself especially in the form of the caudal disc, (2) that in Microcotyle the penis is 

 absent and that the vas deferens and uterus open outwards by distinct apertures, 

 while in Jjcine both have a common opening, (3) that in Microcotyle the vagina is 

 situated on the dorsal median Hue, while in Axine it is situated on the lateral margin, 

 and (4) that in Microcotyle a large number of eggs are found in the uterus at the 

 same time, while in Axine only one egg is found at a time. Parona and 

 Perugia, who studied nearly all the species hitherto known, say, "Differenze 

 salienti fra Axine e Microcotyle stanno nell'avere il primo vagina laterale ed arraata 

 ed il secondo mediana; e nel portare Tin'iinica serie di ventose caudali V Axine e due 

 il Microcotyle." 



According to my own observations every one of the distinctions mentioned by 

 the preceding writers falls away. (1) As already stated, M. reticulata and III. sciaeuie 

 have a decidedly asymmetrical form, while in some other species a slighter degree of 



1). Lorenz — Ueber die Orgiuis. d. Gattung. Axine u. Microcotyle. Wiener Arbeiten., 

 Bd. I, Hft. 3, 1878. 



2). Parona e Perugia — Ees ligusticse, XIV. Contribuzione per una monografia del genere 

 Microcotyle. Estratto dagli Annali del Museo Oivico di Storia Xatur.xle di Geneva, ser. 2, 

 vol. X, 1890. 



3). Sonsino — Di un nuovo Microcotyle raccolto dalV Umbrina cirrhosa. Proc. verb. d. Soc. 

 Tosc. di Scienze 2^atur., 1891. Cited on the authority of St.-Kemy. 



