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TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY, 



tilage was much hypertrophied, and the cysts were little 

 opaque masses about 1 mm. in diameter. The smear con- 

 sists of a mass of spores, two of which are seen in 

 tig'. 7 (d); each is spherical in shape, and possesses 

 two polar-capsules (p.c). The spores are 8-9fi in 

 diameter, and the polar-filaments, many of which are 

 expelled, have a length of about 70/x. There are several 

 retractile oil granules (g) visible, but the stain has not 

 penetrated sufficiently to shew up the nuclei. I could not 

 make out any vacuole in the sporoplasm which would cor- 

 respond to the " iodinophilous vacuole " of a Myxobolus 

 spore. Moreover, the length of the filament is much longer 

 than is usual for this genus. Hence, although there are 

 one or two Myxoboli with spherical spores, I am more 

 inclined to place this new species in the genus Sphcero- 

 spora, as S. platessce, presumably polysporous, and with 

 unornamented, spherical spores. 



We may, therefore, summarize the Myxosporidian 

 parasites of flat-fish as follows : — 



Host. 



Organ or Tissue. 



Parasite. 



Pleuronectes flesus 

 (flounder). 



Gut-wall and 



mesentery. 



Glugea stephani, 

 Hagenm. 



P. platessa (plaice). 



Gut- wall. 



Do. do. 



Do. do. 



Pseudopleuronectes 



americanus 

 (winter flounder). 



Otic-capsule. 

 Gut-wall. 



Sphaerospora 



platessce, n. sp. 



G. stephani, 



Hagenm. 



Rhombus 



(= Stromateus) 



triacanthus (the 



butter-fish). 



Liver. 



Pleistophora sp. 



(probably n. sp.). 



