J. S. Dunkerly 
331 
Ceratomyxa dubia sp. n. (Fig. 2). Host: Cottus bubalis. Habitat: Gall 
bladder. Spore: 1 T*5/x x 8/x. Polar threads 30 [x long. This form approaches 
Leptotheca in proportions, but sporoplasm does not fill spore, and the organism 
is therefore named as a Ceratomyxa, but is, like C. coris Georg, and to a less 
extent C. lata, an intermediate form between these two closely related genera. 
Myxidium intermedium sp. n. (Fig. 3). Host: Pleuronectes flesus. Habitat: 
Gall bladder. Spore: 12/x x 6-7/z, broad ^-shaped like M. incurvatum Thel., 
Fig. 1. Ceratomyxa lata sp. n. x 1900. (a) Spore showing extent of sporoplasm. 
( b) Spore showing sutural line. 
Fig. 2. Ceratomyxa dubia sp. n. x 1900. Polar filaments extruded. 
Fig. 3. Myxidium intermedium sp. n. x 1500. 
but larger and from a different host, no Myxidium having been recorded from 
Pleuronectes. Size alone is not a reliable guide to species as there is apparently 
great variation amongst specimens from different localities, though not much 
in any one infection. Auerbach gives the size of Myxidium bergense spore as 
16*2—19 /lc long x 7-9/x wide, but specimens from Gadus virens caught at 
Millport on the Clyde, which I have carefully drawn with camera lucida and 
compared with a Zeiss 1/100 mm. scale drawn under the same conditions, are 
all very near to the measurements 12-5/x x 5/x. 
Parasitology xii 22 
