o-t BRITISH FRESHWATER RHLZOPODA. 



Ourdmoeba vorax LEIDY in Proc. Acad. Nat. Sci. Phil. 



1874, p. 78; op. cit. 1875, p. 127; and Freshw. Rhiz. N. 



Amer. (1879), p. 67, t. ix, ff. 1-12; MAGGI in Atti Soc. 



Ital. XIX (1876), p. 405; PARONA in Boll. Scient. I, an. 2 



(1880), p. 47; HITCHCOCK Synops. Freshw. Rhiz. (1881), 



p. 7; PERRY in Proc. Amer /Soc. Micr. XII (1891), p. 94. 

 Ouramoeba lapsa LEIDY in Proc. Acad. Nat. Sci. Phil. 1874, 



p. 78. 

 Ouram&ba ARCHER in Q. J. Micr. Sci. XVI, n.s. (1876), 



p. 337, and in Journ. Dublin Micr. Club, III, 2 (1877), 



p. 128. 

 Ouramoeba villosa RAY LANKESTER in Encycl. Brit. ed. 9, 



XIX (1885), p. 842. 



The peculiar caudal appendage, consisting of, usually, 

 from one to three tufts of straight, rigid filaments, 

 emanating from a common stalk, is the characteristic 

 feature of this organism, distinguishing it at once from 

 the larger forms of Amwba proteus, and also from A. 

 villosa. The appendage is dragged behind, in the 

 animal's progress, and appears not to undergo any 

 modification. 



Dimensions : Length 140 /A and upwards ; caudal 

 filaments about 180 /x. 



Ireland (Archer, 1866). 



Mr. Archer was the first to record this organism as 

 British. He exhibited it in 1866, at a meeting of the 

 Dublin Microscopical Society, as a form of Amoeba 

 villosa, and subsequently, on the appearance of Pro- 

 fessor Leidy's work, in which it was treated as 

 generically distinct, he adhered to his conclusions and 

 dissented from those of the Professor, on the ground 

 that the posterior processes were (as he believed) 

 capable of retraction. Leidy found that, except in the 

 possession of this peculiar appendage, Ouramoeba 

 differed in no way from the larger specimens of Amoeba 

 proteus ; though in some instances the posterior part 

 of the body assumed " a mulberry-like appearance, 

 which simulated a patch." Archer describes the pro- 

 longations as "forming a compact bundle, linear, often 



