has greatly increased in length, bein^ now about 0.1^0 inm. , 

 bat this is accompanied by a decrease in width. -^eoause 

 of this increase in length, the posterior enu is often 

 doubled bac}- in the Qflg* The primitive digestive tract 

 is larger ami th* geria balls are nore conspicuous* j&br 

 the first time th<* cilia on the surface of th^ body are 

 clearly distinguished* The activity now is often violent, 

 the rairacidiura lunging ba<^ and farth against the operoulum. 

 The egg is now r*ady to hatch* Pigure 16 ehowe another 

 mature miraoidiua also r'mdy to hat<^t, in nhioh Uie 

 central nervouu system is apparent, 



I am inclined to believe that studies on the development 

 of other echinostoiaes will shew the above description of 

 development to be quite characteristic of the foully* This 

 opinion in based upon the fact that distantly related 

 families show quite similar development cf the miraaidiuou 

 Because of the opaque condition I was unable to determine 

 whether the t**o florae oells ar joined by short nearly 

 straight capillaries cr if the capillaries are long and 

 much coiled. The excretory pores are located on each side 

 near the posterior end. The excretory system cf most 

 miracidia seems to consist of but two flame cells anu two 

 capillaries. Loo SB (1896, pi* XI and XU) find s the 

 excretory syetem of the miraoidium of G astro discus aegyptious 

 (Cobbold), Pas t>\ re thy 1 ax gregarius Lgass and 



hepatioum varlet, aegyptioa*, follcwing this plan, Looss 

 (1892, pi. XLX) again sliows that in "Amphisto uum 



