The fauiily Koellikeriadae. 145 



simple intestinal coeca. Genital opening below bifurcation, witli 

 genital canal. Parallel to this canal runs tlie uterus which opens 

 near the raouth. Eggs bean sliaped 16 X 10 [x. Animal 10 X 6 mm. 



Dichjmostoma bipartitum (Wedl, 1855), (Wagenek's first form). 

 Identical with Didijmosoon micropterygis of Richiaedi. Cysts with 

 two dissimilar individuals, one large as a pea with two regions, 

 filiform and globular; the other minute without posterior swelling. 

 Mouth sucker present, but no pharynx; short Oesophagus bifurcates 

 in two simple intestinal coeca. Uterine opening near mouth. Eggs 

 21 X 11,6 /". Small individual has mouth sucker and larger and 

 longer neck. Measures 3,5 X 2 mm. The smaller is 2,5 mm in length. 



Dklymocystis ivedli (Wagener's third form). 



Cysts on gills contain two equal individuals with elongated 

 body, the abdominal region of which is divided into two parts, a 

 caudal recurved cylindroid and a larger anterior part indented by 

 a groove from which the head emerges. No swelling of cephalic 

 end, no mouth sucker, double pharynx. Oesophagus divides into two 

 intestinal coeca. Genitalia as in other forms. 



Apparently then at least three different species have been 

 known by the same name but it seems doubtful that new generic 

 names should be established on such slender basis as stated in 

 Ariola's descriptions and 1 prefer to class all three as Koellikeria, 

 especially since other species of this genus possess mouth suckers. 



Koellikeria (Didymozoon) scombri Taschenbeeg. 



Body elongated, rounded at both ends, neck only slightly nar- 

 rower than the body. Pharynx spherical, intestine present. Opening 

 of Uterus on a little papilla et anterior end of animal, Length 

 18 mm. Cysts on the gill Covers of Scomber colias. 



K. (D.) pelamydis Taschenbeeg. 



Body very long, slightly narrowed posteriorly and sharply 

 pointed; neck thin, head widened, spoon shaped. Pharynx sphe- 

 rical. Intestine lacking. Length 30 mm. Cysts between gill leaf- 

 lets of Pelamys sarda. 



K. (D.) sphyraenae Taschenberg. 



Body Short, compressed, rounded posteriorly. Neck sharply 

 marked off from body; head very little broadened. Pharynx oval. 



