SEA-FISHERIES LABORATORY. 307 



II. 



Mr. Johnstone kindly sent me a couple of smears 

 made from the contents of one of the cysts above 

 described, expressing his opinion that a Myxosporidian 

 parasite was concerned, and asking me to identify it. On 

 examining the smears, I saw that they consisted entirely 

 of spores, evidently belonging to a Phaenocystan parasite, 

 for two brightly refringent polar capsules were visible in 

 each. One of the slides was stained with Heidenhain's 

 iron-haematoxylin, the other with thionin. For some 

 reason or other the first method did not prove a success, 

 the stain persisting in the spore-wall in a rather blotchy 

 manner, and obscuring the contents ; while the polar 

 capsules did not retain it at all. By the second method 

 the spore-wall itself remained unstained, the polar 

 capsules were deeply stained, and the various nuclei, 

 though not retaining the stain as much as was desirable, 

 eould often be made out with a little trouble. 



Two spores are seen in fig. 2. In shape they are 

 slightly ovoid, their dimensions averaging 10 jm in length 

 by 8 /ul in breadth. The two polar capsules (p.c.) are 

 situated near one end of the longer axis; the length of 

 each varies from 3J to 3J jm. Unfortunately, I could not 

 find a single spore in which either or both of the polar 

 capsules had the filament evaginated. This was a little 

 surprising, as in a similarly prepared slide of another 

 parasite (SpJiaerosjjora platessae) which I have previously 

 characterised,* the stimulus of spreading the smear had 

 caused many of the capsules to evert their filament. So 

 that I have not been able, so far, to ascertain the length 

 of the filament in the spores under discussion. Occupying 

 a considerable portion, of the sporoplasm is a large, well- 

 Woodcock, Proc. L'pool Biol. Soc, Vol. XVIII., p. 140 (1904). 



