10 BRITISH FRESHWATER RH1ZGPODA, 



In the early part of the year 1841 Ehrenberg read 

 a paper before the Kgl. Akademie der Wissenschaften 

 of Berlin in the course of which he described amongst 

 other species two filose Conchulina under the names of 

 Difflugia areolata and D. acanthophora, the former 

 having " postica parte nuda " and the latter " postica 

 parte tribus quatuorve aculeis armata." 



Later in the same year Dujardin, in his ' Histoire 

 naturelle des Zoophytes : Infusoires,' established the 

 genus Euglyplia and described as two species E. tuber- 

 cidata and E. alveolata, his brief diagnosis of the 

 former being " tet orne de tubercules arrondis," and 

 of the latter " tet orne d'impressions polygonales, 

 regulieres." He had found them in vessels (or tanks) 

 of fresh water with aquatic plants taken from marshes. 

 E. tubercidata is a well-defined and figured species, 

 and there can be no doubt of its identity, although 

 he mentions that he has seen an empty test with 

 many spines " en arriere " (i. e. on the fundus) ir- 

 regularly placed as in the next species described 

 (alveolata), for we may dismiss this observation as per- 

 taining to another species, most probably Euglyplia 

 cilia ta. E. alveolata is not so clearly described, indeed 

 Dujardin says that he has only seen the tests and 

 mentions its analogy with the preceding species (E. 

 tubercidata), of which he says one might be tempted to 

 consider it as only a variety, especially as they were 

 together in the same vessel. He describes and figures 

 one form with five scales on the fundus modified into 

 long, slender spines, and another without any spines, 

 and mentions differences between them in the disposi- 

 tion of their scales 



Ehrenberg's memoir was not published until after 

 Dujardin's work had appeared, and in his description 

 of the plates on which Diffiugia acaidhopJiora and D. 

 areolata are figured he refers Dujardin's Euglypha 

 alveolata to them, saying that it therefore falls ; and 

 he also says that " Euglpha tnberculosa " (using the 

 name applied to this species by Dujardin in his 



