SEA-FISHERIES LABORATORY. 147 



the smaller ones are more peripherally situated, though 

 there is no regular increase in size as one passes inwards. 

 The only other point to note is a series of tiny spherules 

 (sph.), each with one, or sometimes two granules, at the 

 outer margin of the cortex, almost abutting on the mem- 

 brane (ect.), but I have seen no transition between these 

 and the deeply-staining reticula, nor are they obvious in 

 all my sections. I should add that in fig. 3 these latter 

 are more closely packed and rather more strongly-stained 

 than in fig. 4. 



In endeavouring to arrive at some idea of the nature 

 and affinities of these remarkable cysts it will be most con- 

 venient to commence by the process of elimination. 

 In the first place we have, certainty, not to deal with 

 a Trematode or other Metazoan parasite. Further, Dr. 

 Nabarro and Professor Oliver, who have kindly examined 

 it, are of the opinion that the cysts are the result of neither 

 a bacterial nor a fungal infection, and, indeed, it is almost 

 inconceivable that an ordinary cell could be so enormously 

 hypertrophied by bacterial or hyphal invasion, and retain 

 as much of its structure as these bodies do (compare the 

 amoebocytes and connective-tissue cells around). More- 

 over, Mr. Pollard, of the Bacteriological Laboratory at 

 University College, has stained sections for me by the 

 usual methods adopted for Bacilli, &c, without result. 

 The localized and restricted nature of the infection is also 

 against this view, the cells around being quite normal. 

 So that we may dismiss the idea of the cysts being caused 

 by a bacterial or hyphomycetic parasite. Each cyst- 

 like body is one organic unit. 



I can only think of two remaining hypotheses, 

 namely, that the bodies must represent either eggs or 

 parasites. Now, although, as stated above, it was 

 absolutely impossible that thev were the eggs of some 



