CESTODARIA 403 



line and not on the edge of the body ; (b) in both famihes the 

 uterus and vagina run parallel to and in the same dorso- 

 ventral plane with each other along the longitudinal axis of 

 the body, and in both the testes occupy only the anterior end 

 of the body ; (c) in both families the ovary is bipartite, and 

 (d) in both calcareous corpuscles are absent ; (e) in both 

 families hexacanth embryos have been found ; ^ and (/) a 

 reticulate type of excretory system is common to both. On the 

 other hand, in the Amphilinidae, (a) the uterine and 

 vaginal apertures are situated at opposite ends of the body and 

 are in all cases situated on or near the body edge ; (b) the uterus 

 and vagina run in opposite directions from the ovary, the former 

 anteriorly and the latter posteriorly ; (c) the ovary is uni- 

 partite ; (d) calcareous corpuscles are present ; (e) hexacanth 

 larvae have not been found, the larva being of the ten-hooked 

 kind ; and (/) the excretory system consists of two main longitu- 

 dinal canals only and minor regularly arranged looped canals. 

 I am thus unable to agree either with Monticelli (15) in believing 

 that A m p h i 1 i n a and ' A m p h i p t y c h e s ' (CI y r o c o t y 1 e) 

 are closely related forms, or with Lonnberg (12), who is of opinion 

 that the Caryophyllaeidae differ essentially from the 

 Gyrocotylidae in being secondarily monozoic forms, the 

 Gyrocotylidae being, in his opinion, primarily monozoic. 

 I cannot find that either of these authors have advanced any 

 valid reasons for these opinions. It is true that Gyrocotyle 

 differs from all Caryophyllaeidae in possessing an 

 anterior sucker and a posterior ' funnel ' (with muscular and 

 nervous modifications to match), but the extremities of these 

 animals can develop almost any kind of process, as we see in 

 the Caryophyllaeidae, and this difference, as also the 

 minor differences in the conformation of the genitalia and in 



^ Both Spencer (24) and Hungerbiihler (9) found in certain species of 

 Gyrocotyle ten-hooked larvae similar to those of Amphilina, 

 while in G. urn a Lonnberg {'Biol. Foren. Forhandl., Verhandl. d. 

 biol. Ver. in Stockholm ', vol. ii, 2, p. 55, 1890) found larvae apparently 

 altogether devoid of hooks. The significance of these facts is as yet 

 obscure. 



