ON AMPHILINA PARAGONOPORA 53 



already mentioned, that they cannot be flattened out between 

 glass slides. We must, therefore, assume provisionally that 

 these masses represent as a rule bodies which would, in the 

 ordinary course of events, become transformed into active 

 A m p h i 1 i n a p a r a g n o p o r a . They undoubtedly represent 

 a phase in the life-history of A m p h i 1 i n a p a r a g o n o p o r a , 

 and they will be described and discussed in detail in Part II. 



(b) The Reproductive System. 



The general plan of construction of the reproductive system 

 of Amphilina paragonopora (PL 3, fig. 8) is similar 

 to those of A. foliacea (vide PI. 3, fig. 9, adapted from the 

 figures by Salensky and Hein) and A . 1 i g u 1 o i d e a (as 

 described and figured by Janicki), but, as we shall see later, 

 there are a few noteworthy differences. Previous to describing 

 the genitalia of A. paragonopora in detail, it is necessary 

 to decide as to which surface of the animal is to be labelled 

 ' dorsal ', since previous authors have been by no means 

 unanimous concerning even this essential preliminary : thus 

 e.g. while Salensky and Wagener consider that the side of the 

 body on which the uterus arises from the ovary is the left, 

 Monticelli assumes that it is the right (the view taken by 

 the present writer), while other authors apparently avoid the 

 subject. In typical mesozoan Cestoda it is the rule that the 

 surface of the body to which the ovary is the more adjacent 

 is to be regarded as the ' ventral ' surface ; and that the ootype 

 is situated on the ' ventral ' side of the ovary. In Trematodes 

 also, it is a rule that the vitelline ducts enter the ovary on its 

 ' ventral ' aspect, w^hatever may be their subsequent course. 

 If we apply these rules to Amphilina paragonopora, 

 then PI. 3, figs. 8, 10, 11, and 12 represent the organs as seen 

 from the dorsal ^ aspect, as proved by the study of serial 

 transverse sections. It will be observed from these figures 

 that when viewed from the dorsal aspect, (a) the uterus arises 

 from the right side of the ovary, runs forward nearly to the 



^ Wagener's ventral aspect. 



