1§4 S- <^0T0. 



HiutereiKlo mit den Saugnäpfeu noch etwas schiefer 7A\v Achse des Körpers steht als 

 bei den typischen Microcotylen." In the same year Lorenz') described another 

 species, ^^. mnrmyil, from the gill of Vagcllns mormyrus, and shed much light on its 

 anatomy and histology. 



Par on a and Perugia-^ have recently (1889 k 1890) described four additional 

 species, r/c. A/". sar(ji from the gill oi Saryus Fiondeh'tii, S. (ninularis, and S. rulii<iris, 

 M. alcedinis from the gill of Siiimis dlcedo and i\Lcna vuhjaris, M. tracliini from the 

 gill of Trach'uius radiatus, and 3/. saljiKC from the gill of Box saljut. These writers 

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

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

 S onsino^) described a new species from the gill of Umhrbut cirrhosn, and named it 

 jl/. Vanccrii. 



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

 not be separated from Ax'me. Lorenz, on the other hand, decidedly maintains its 

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

 (1) that Microcoti/le is perfectly symmetrical in external form, the symmetry showing 

 itself especially in the form of the caudal disc, (2) that in Microcoti/le the penis is 

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

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

 situated on the dorsal median line, while in Axiite it is situated on the lateral margin, 

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

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

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

 salienti fra A. cine e Microcotiile stanno nell'avere il primo vagina laterale cd armata 

 ed il secondo mediana; e nel portaro un'unica série di ventose caudali VA.ciite c due 

 il MicrocotiileJ^ 



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

 the preceding writers falls away. (1) As already stated, 3/. reticiddUt and M. sciaeiiie 

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



1). Lorenz — Ueljer die Orgxnis. d. Gattung. Axiue u. Miorocotyle. Wiener Arbeiten., 

 Bd. I, Hft. 3, 1878. 



2). Parona e Perugia — Res ligusticce, XIY. Contribuzione per una monografia del genere 

 Microcotyle. Estratto dagli Annali del Museo Civico di Storia Naturale di Geneva, ser. 2, 

 vol. X, 1890. 



3). Sonsino— Di un nuovo Microcotyle raccolto dall' Umbrinacirrhosa. Proc. verb. d. Soc. 

 Tosc. di Scienze Xatur., 1891. Cited on the authority of St.-Ileuiy. 



