100 



THE CESTOIDEA 



comparable with the Laurer's canal of the Trematode, which has 

 lost its opening (cf. the receptaculum vitelli of Aspidog aster). 



FIG. II. Monozoa. 



1. Generative system of Amphilina foliacea, Rud. (combined from figures by Salensky and 

 Wagener), out of the sturgeon, a, sucker, with retractile muscles (?) or gland cells (?) ; b, 

 uterine or birth pore ; V, uterus ; c, vitellariuiii and vitellarian duct ; d, germarium ; its duct 

 'opens into the ootype ; e, the vaginal pore ; e', the vagina, dilated in its upper part ; /, sperma- 

 theca ; g, male pore ; h, cirrus ; i, sperm duct, which is represented as less convoluted than it 

 is in reality, the wide, convoluted region being the seminal vesicle ; .?', testes ; k, shell gland. 



2. The larva of Amphilina foliacea removed from the egg (after Salensky). The upper end 

 is ciliated ; the other end is slightly cupped and carries ten hooklets (5) ; o, gland cells opening 

 anteriorly. 



3. The same from behind, showing the ten hooklets, arranged round the terminal cup. 

 (Orig.) 



4.Gyrocotyle urna, Wagn. Outline of the ventral surface showing external apertures and 

 nervous system (after Spencer), a, peculiar frilled organ ; b, uterine pore ; c, terminal sucker ; 

 d, the left excretory pore ; the right one is not lettered ; e, vaginal pore ; g, male pore on the 

 margin ; n, lateral nerve ; o, anterior commissure ; p, posterior commissure. 



5, 6, 7 represent the arrangement of the excretory system in Caryophyllaeus. 5. The mobile 

 organ, dorsal view. (Modified from Fraipont.) 6. A transverse section of the body. (After 

 Will.) 7. Dorsal view of body (orig.). a, b, c, d, e, the five descending canals of one side ; 

 these are connected by a network throughout their course, as is shown well in 5 and 7. At 

 the hinder end of the body the ten canals open into a contractile sac. /, g, the "ascending 

 canals " which, in the greater part of the body, lie superficially to the descending canals (6), but 

 in the neck sink into the "medullary region." [In 7 the canal marked "/" should be "</."] 

 These ascending canals are connected by a fine, superficial network (/i), which carries numerous 

 flame cells, which are indicated in 6 ; fc, the longitudinal, muscular layer separating the paren- 

 chyma into a cortical zone, in which the excretory canals lie, and a medullary region containing 

 the genital organs. I, m, n, o, p, the five longitudinal nerve cords of the left side ; n is the 

 stout lateral or marginal nerve corresponding to that in 4. 



As was pointed out above (Trematoda, p. 87), the vagina or 

 copulatory duct of the Heterocotylea appears to have no homologue 



