146 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



closely aggregated. (A portion of the same cyst more 

 strongly magnified is seen in fig. 6.) The most external 

 layer belonging to the parasite is a thick, faintly- 

 staining', structureless membrane, which I have denoted 

 by (ect.). Next comes a thick zone (end.), more deeply- 

 staining, of a finely granular nature, the greater part of 

 which presents a most unusual appearance, and gives the 

 organism its remarkable character. Centrally is what 

 can only be a nucleus (N), although of relatively huge 

 size as in fig. 4, which is a section through another, 

 larger, cyst, from underneath the skin. In each nucleus 

 are several nucleoli (n), or rather kaiyosomes, since they 

 retain the chromatic stain. Fig. 5 is part of the nucleus 

 drawn under a high-power, and shews a faintly-staining, 

 irregular reticulum, which traverses a finely-granular 

 ground-substance, with karyosomes of all sizes, the larger 

 being vacuolated and the smallest little more than 

 granules. The nuclear-membrane is very thin and 

 extremely irregular, and sometimes appears only as a 

 boundary between the nucleus and the inner limit of the 

 cortical region (shewn on the left in the fig.). 



In fig. 6 I have attempted to indicate the appearance 

 of a portion of the cortex, as seen under a high power. It 

 consists of a finely-granular matrix, staining with the 

 plasma stain, in which are innumerable, usually separate, 

 reticula or net work (ret.), in every variety of shape and 

 size. These stain up deeply with chromatic stains, and, 

 so far as I can make out, are made up of threads of rodlets 

 or granules, not easy to resolve. Each network is 

 developed round a centre (which stains sometimes less, 

 sometimes more, than the general ground-substance) ap- 

 parently at its periphery. These structures do not com- 

 mence quite at the external limit of the cortex and they 

 cease some distance before its inner limit. On the whole, 



