550 MONTGOMERY— MORPHOLOGY OF THE [Apnl 24, 



end, terminal or dorsal, and into it open usually two but sometimes 

 four or even six main canals (Braun, 1893). In the larva (mira- 

 cidium) of Distomum there is a single large flame cell on each side 

 of the body with a capillary opening on the surface (Coe, 1896). 

 Bugge (1902) has shown that each flame cell and its capillary " de- 

 velop out of one cell and are to be compared with a unicellular 

 gland," a practical confirmation of Lang's (1884) suggestion. 



(3) TemnocephalecB. 

 The excretory system of these curious forms has been made 

 known particularly by Weber (1889). There is a pair of sepa- 

 rated dorsal nephridiopores, each communicating with main canals 

 that branch and anastomose with those of the opposite side, so 

 that the general arrangement is like that of the Trematoda. 



(4) Cestoda. 



Here the main canals have no dendritic branching but frequent 

 anastomoses, so that quite generally each proglottid has one or two 

 pairs of transverse canals connecting the main lateral ones ; the main 

 lateral canals open by a common contractile vesicle at the posterior 

 end of the ripest proglottid (Pintner, 1896). In the most detailed 

 contribution on the subject (Bugge, 1902) muscle fibrils of the main 

 canals are described and also valves within them (the latter dis- 

 covered by Kohler in 1894) ; in the cysticercus stage foramina 

 secondaria were found connecting the main canals with the surface 

 of the body. Bugge uses the term " Wimperflamme " to include 

 the " Terminalzelle " (" Geisselzelle, Deckzelle"), with the 

 " Wimper " and " Trichter " and " Capillare." He traced such 

 Wimperflammen as outgrowths from the walls of the main canals : 

 a cell of the latter projects outwards then divides into a group of 

 four; of these four one forms three Trichter and the capillary 

 (the cavities of these parts being intracellular), while each of the 

 three others becomes a flame cell with a ciliary flame. 



Anatomically considered there are two main kinds of excretory 

 organs in the Platyhelminthes : (i) with numerous serial excretory 

 canals, found only in the Tricladidea; and (2) with only one or 



