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PROGRESS OF MICROSCOPICAL SCIENCE. 
Mr. Archer s Opinion of the American Ouramoeba. — In a paper read 
before the Philadelphia Academy, on April 20, Professor Leidy 
remarked that his description of the curious rhizopod he had named 
Ouramoeba, in the Proceedings of May 12, 1874, having been noticed 
by Mr. Archer, of Dublin, this gentleman had directed his attention to 
notices of the same animal described in the ‘ Proceedings of the Dublin 
Microscopical Club’ for Feb. 1866 and Oct. 1873. In these notices 
Mr. Archer regards the animal only as an Amoeba villosa in another con- 
dition from that ordinarily observed. Mr. Archer’s description clearly 
refers to the same animal as that named Ouramoeba, in which he aptly 
compares the bunch of tail-like appendages to “ a bundle of dipt- 
candles,” and it is of some interest to know that the singular creature, 
like so many other rhizopods, is common to Europe and America. 
While Mr. Archer regards the “Amoeba with remarkable posterior 
linear processes ” * as exhibiting another condition of existence of an 
Amoeba from the one usually observed in the genus, he gives no 
evidence that such is the fact. Until this is proved to be the case the 
peculiar character of the animal justifies its separation as representing 
a distinct genus with the name of Ouramoeba. 
Since the latter was first noticed, many additional specimens have 
been observed ; and though, as in the case of rhizopods generally, they 
exhibit considerable variation, it appears that several species may be 
distinguished. 
The genus may be thus characterized : 
Ouramceba. — Body, as in Amoeba, consisting of an ever-changing 
fluctuating mass of jelly, composed of a granular entosarc, including a 
contractile vesicle and a discoid nucleus, and defined by a clearer 
ectosarc. Pseudopods usually digitiform, projecting anywhere, but 
usually in a direction differentiated as forward, and composed of 
extensions of the ectosarc closely accompanied by included extensions 
of the entosarc. Posterior part of the body furnished with one or 
more tufts of non-retractile, rigid, linear appendages, branching 
radically from common points in the vicinity of the contractile 
vesicle. 
Ouramceba vorax. — Body active, usually ramifying forward from a 
median stock extending from the posterior blunt extremity. Posterior 
appendages numerous, originating in several tufts up to five or six, 
from one-third to nearly the length of the body, linear, straight or 
curved, uniformly cylindrical, or here and there contracted, com- 
mencing in a pointed manner from a common root, and terminating 
obtusely. Length of body, from 1 to ^ of a mm. ; length of ap- 
pendages from one-third to nearly that of the body. 
The creature consumes multitudes of diatoms, desmids, and fila- 
mentous algae. Found in springs and ponds, near Darby Creek, Dela- 
ware County, Pennsylvania. 
Further observations have induced me to believe that the animal 
* ‘Pruc. Dublin Micr. Club,’ Oct. 1873, p. 314. 
