358 University of California Publications in Zoology [Vol. 19 



cerearia of Eehinostoma rcvolutum many times, but upon a more 

 careful study the two excretory tubes and pores could also be seen. 

 This proved to be one of the most difficult points to determine because 

 of the deceptive appearance of the muscles. That the wide variety of 

 excretory parts in the tail of echinostomes exists as described by Faust, 

 seems very improbable in such a well defined family and especially 

 so since Looss, Lebour, Cort, and myself have found a uniform type 

 with two excretory pores in the tail. 



Nowhere in the middle or posterior parts of three of his cercariae 

 does Faust find flame cells. That they exist there I feel quite positive. 

 The failure to see flame cells and tubules in these regions is probably 

 due to the heavy cystogenous glands in these three species. Only at 

 the anterior end where there are no cystogenous glands does he find 

 the flame cells. In Cerearia acanthostoma, however, he shows flame 

 cells directly connected singly with tubes which are equivalent in the 

 other species to the anterior tubes of the bladder. That these flame 

 cells join directly to the tubular division of the bladder is improbable, 

 since in no cerearia where the excretory system has been carefully and 

 completely work out does this occur. Rather do the flame cells, by 

 means of their capillaries, unite with accessory collecting tubules. 



At the anterior end in each of these four new echinostome cercariae 

 described by Faust, he shows three flame cells on a side. These three 

 flame cells are probably present in all echinostome cercariae. Their 

 arrangement and attachment is probably a family characteristic. I 

 feel quite sure, however, that these three flame cells do not unite with 

 the concretional tubas of the bladder as shown in Cerearia trisolenata 

 and Cerearia ehisolenata, or even as in Cerearia acanthostoma. As 

 stated above, capillaries are not known to unite with parts of the 

 bladder. In the arrangement and attachment of these three anterior 

 flame cells, Cerearia biflexa (Faust, 1917, fig. 138) is much like the 

 cercariae of Echinostomum revolutum and " Distomum echinatum" 

 as described by Looss. But even in Cerearia biflexa I am inclined to 

 believe that the tubule to which the three anterior flame cells are 

 attached does not bend forward and join the tube of the bladder but 

 proceeds much farther posteriorly, joining the tube of the bladder in 

 the region of the acetabulum (fig. 47. 2a). The arrangement shown 

 in Cerearia biflexa (Faust, 1917, fig. 135) by which the fine capillaries 

 join the tubes of the bladder is also an improbable arrangement. These 

 capillaries are probably equivalent to the branching of the tubes of 

 the bladder as shown by Lebour (1912, pi. XXVIII, figs. 9, 13, 17). 



