16 ILLINOIS BIOLOGICAL MONOGRAPHS [234 



15(12) Vitellaria lateral to crura 



Ventral acetabulum conspicuously developed 



Bothriogaster Fuhrman 1904 



Up to the present the only genus in this family represented in North 

 America is Cyclocoelum and for this reason the other genera are not dealt 

 with in the following pages. 



CYCLOCOELUM 



Historical. The question of the type for this genus is indeed a com- 

 plicated one and as Stiles (1908) has said "well represents a ship without 

 a rudder." Liihe accepts the designation of Hoyle (1888) and takes issue 

 with Looss who by elimination accepts Monostomum prismaticum as type. 

 Stiles (1908) presents a third view in which he says that the name Mono- 

 stomum is a synonym to Festucaria by priority rule, since Zeder deliber- 

 ately renamed the genus Festucaria Schrank (1788). 



A critical study of the literature involved brings to light certain facts 

 on this point which seem to the writer to be worthy of space here. The 

 name Festucaria was proposed by Schrank (1788) for two species Festu- 

 caria anatis and Festucaria strigis. These species were described by Goeze 

 (1782) in Klasse II of his family (genus) Planaria as "rundlichte oder 

 walzenformige Plattwurm" of which he says there are two genera. Only 

 one of them is of concern here and is described by Goeze (1782:173-174) as 

 having a single mouth, ("mit einfacher Miindung"). 



From the context of the description one is led to believe that these 

 worms were collected by Goeze since he says, "Ich, * * * habe sie nur 

 in zwo Arten von Vogeln gefunden; in einer zahmen Ente, und in einer 

 grauen Weideneule." He follows this with a description of the worms in 

 situ as well as when he placed the intestine of the host in water where the 

 worms "loosed themselves/' 



The type of the genus Festucaria becomes by page precedence Festu- 

 caria anatis Schrank (1788). This purports to be the same worm described 

 by Goeze (1782:174) as follows: "In den Dedarmen einer Ente sassen 

 hin und wieder kleine gelbliche Knotgen. Da ich einige abnehmen wollte, 

 merkte ich, dass sie vest anklebten. Als ich sie ins Wasser brachte, gaben 

 sie sich los, und ich erkannte sie fur rundlichte Plattwiirmer mit einer 

 Miindung." The description of his figure 9 plate 13 adds "(a) die einfache 

 Miindung mit 2 Punkten; (b) eine Art von Maul dariiber." From the 

 description and the figures this appears to be the crown of spines which 

 Goeze mistook for a mouth. 



The description of Schrank (1788), based on Goeze (1782), runs as 

 follows: 



Splitterwurm Festucaria 



Ein langlichter, einformiger Wurm vorne mit einer einzigen Sauge- 

 miindung. 



