334 ERNEST CARROLL FAUST. 



this scheme the echinostome larvae with three flame cells on a 

 side are given the formula of a, while those with other flame cells 

 distributed along the tertiary collecting tubule behind the a 

 group would be designated as a + P n . The full scheme for 

 litteral formulae for the larval and adult flukes where the flame 

 cells have been best analyzed is presented in the following table 



(Table II.). 



TABLE II. 



GENERAL FORMUL.-E FOR FLAME-CELL ARRANGEMENT IN DISTOMATA. 



ECHINOSTOMES. 



Cercaria chisolenata ~\ 



Cercaria trisolenata r ......... a 



Cercaria biflexa 



Cercaria complexa 



. Y ......... a + /3 



Cercaria acanthostomaj 



XlPHIDIOCERCARI.-E. 



Cercaria ttifurcata .............. a' + 0' + a" + 0" + y" 



Cercaria candelabra ............. a' + 0' + y' + a" + 0" 



Cercaria isocotylea .............. a' + /3' + 7' + d' + e' + ' + a." + /3" + y" 



BRACHYCOELIID^E ................. a' + /3' + a" + /3" 



PLAGIORCHIID^E .................. a' + 0' + y' + a" + 0" + y" 



ALLOCREADIID^:. 



Allocreadium isoporum .......... a' + 0' + y' + !?' + a" + /3" 



Acrolichanus petalosa ........... a' + 0' + a" + j3" + y" + <p" 



FURCOCERCARI.. 



Cercaria of Schislosoma japoni-^l 



cum ....................... (a +/3 



Cercaria donthitti 



Cercaria elephantis 



Cercaria furcicauda ") 



Cercaria emarginatx ........... ["a + /3 +7 



Cercaria douglasi 



Cercaria robusticauda 



y 



. 



Cercaria quattuor-solenata ..... 



Cercaria rhabdocizca ............ a +/3 +7 + i> +e 



DESCRIPTION OF NEW SPECIES CITED IN THIS PAPER. 

 Cercaria complexa nov. spec. (Fig. 2.) 



Systematic position: echinostome larva. 

 Parthenita: redia. 

 Host : Planorbis trivolvis Say. 



Habitat and time of collection: drainage ditch, Urbana, 111., 

 1918. 



