68 FRESH-WATER RHIZOPODS OP NORTH AMERICA. 



After publishing a brief notice of Ouramceba in the Proceedings of the 

 Academy of Natural Sciences of Philadelphia for 1874, Mr. Archer, of 

 Dublin, had the kindness to direct my attention to a description of the same 

 animal, by himself, in the Journal of Proceedings of the Dublin Micros- 

 copical Club for 1866, page 56, and 1873, page 314. This I was delighted 

 to see, as I felt that it confirmed my observation of the existence of this 

 curious and enigmatic variety, or species 



There can be no question but that Ouramceba is the same creature as 

 the one which had been previously discovered and described by Mr. Archer. 

 This able authority, however, regarded the animal only as a remarkable 

 variation from ttie Amoeba villosa of Dr. Wallich, and in this light still con- 

 tinues to view it. as we learn from the following report of the Proceedings 

 of the Dublin Microscopical Club, published in the Quarterly Journal of 

 Microscopical Science for 1876, page 337: "Mr. Archer further presented 

 a preparation in Beale's carmine fluid of the curious Amoeba form, plus a 

 cluster of finger-like posterior appendages — Ouramceba, Leidy, which, 

 however, did not cause any contraction of the processes, a fact, so far 

 capable of being urged by Prof. Leidy in favor of his views ; but on the 

 other hand the gathering abounds with specimens of the ordinary character, 

 that is, without the faintest evidence of any linear processes — simple Amoeba 

 villosa (princei^s), — but, the appendages apart, quite identical with the 

 so-called Ouramceba " 



Though none of the individuals of Ouramceba vorax which I have ob- 

 served equaled in size the largest ones of Amoeba proteus, in all other 

 respects — the possession of the caudal filamentous appendages alone ex- 

 cepted — I remarked no difference. 



Mr. Archer speaks of the animal observed by him as a form of Amoeba 

 villosa of Dr. Wallich, and refers to " the presence of a large and numerous 

 tuft of very long prolongations commonly issuing from just beside the 

 villous patch." 



In Ouramceba vorax I have at no time observed a villous patch, though 

 in several instances I have seen the posterior part of the body in its con- 

 traction assume a mulberry-like appearance which simulated such a patch, 

 as seen in fig. 9, pi. IX. 



The filamentary caudal appendages of Ouramceba vorax consist of from 

 one to half a dozen distinct tufts, usually collected into a single bundle 



