AOANTHOCYSTIS SPINIFEEA. 



55 



Diameter of envelope 40 ju, to 60 /x ; length of spines 

 from one third to one half the diameter of the envelope. 



Habitat. — Moorland pools and vegetation in still 

 water. 



Distribtitiov . — England. — Sheffield district, W. 

 Yorks.; Derbyshire (-BroiOTi). 

 Iekland. — ? Wicklow (Archer). 



In the original description of this species by Greeff 

 the included yellow bodies were considered to be 

 charactei-istic; they were also observed by Archer, but 



Fia. 190. — Acanthocystis spinifera. x 300. (After Greeff.) 



Hertwig and Lesser did not find them, their place being 

 taken by numerous " chlorophyll-green granules " ; 

 Archer also observed these and remarked that they 

 occurred in " never the abundant quantity mostly 

 characteristic of A. cliastophora ." The yellow globules 

 Archer considered to be of an oily nature and 

 agreed with Hertwig arid Lesser in the supposition 

 that their presence or absence was probably determined 

 by the " varying degree of nutrition of the organism." 

 I'his no doubt is correct if, as seems probable, they 

 serve as a reserve supply of food. 



The A. spinifera of Penard is a distinct species, but 

 Penard's illustration and description of " J. pertijana 

 Archer " show that he had probably this species under 

 observation at the time. 



