466 W. N. F, WOODLAND 



are necessarily displaced from their primitive anterior position), 

 the three sexual apertures are all close together, the ovary is 

 bipartite, and a hexacanth larva is present. 



I would not, however, go so far at present as to follow Liihe 

 (13) in actually grouping the Caryophyllaeidae with the 

 Diphyllobothriidae in his Order Pseudophyllidea, 

 because for me the monozoan character of the Paralinidea 

 is a fundamental one, and to me it is inconceivable that the 

 Paralinidea have become secondarily monozoan. It is also 

 well to remember that the A m p h i 1 i n i d e a may not be so far 

 removed from the Paralinidea as their existing structure 

 would seem to indicate, for the simple reason that this structure 

 is, in part at least, an obvious adaptation to the mode of life 

 of Amphilina. Amphilina is parasitic in the body- 

 cavity and not the gut of the fish, and it can only liberate its 

 larvae to the external world by boring through the body-wall 

 of its host (hence the huge boring apparatus I have described 

 (28) and the extreme anterior position of the uterine pore) 

 and has to retain its larvae until it has penetrated to the 

 outside of the fish (hence its enormously elongated uterus — 

 a duct which Avould not need to be so elongated if, as in the 

 Paralinidea, the parasite could continually shed its eggs 

 into the intestine). These bionomic necessities must have 

 caused a great transformation in the entire anterior end of the ^, 



animal and especially in the arrangement of all the contained ^ 



ducts, and it is therefore possible that even the posterior 

 position of the vas deferens and the vagina (the openings of 

 which must remain adjacent) is to be regarded as but another 

 indirect concomitant of the general rearrangement. In other 

 words, the original plan of the genitalia in Amphilina is 

 possibly largely masked by specialization and, in the light of 

 present knowledge, it may be incorrect to conclude that 

 Amphilina is more separate genetically^ from the Para- 



1 The fact that in both the Paralinidea and Amphilinidea 

 ten-hooked larvae have been found may be called to mind in this con- 

 nexion. I may here remark that Sanguinicola (still included in 1916 

 by Cholodkowsky (3) in the Cestodaria) is now known not to be a Cestode : 



