Decembek 2, 1898.] 



SCIENCE. 



781 



The filamentous appendages, which consti- 

 tute the only peculiarity of the form, are 

 not, as he and Archer suj)posed, extensions 

 of the body- substance; they are, on the con- 

 trary, mycelial hyphse, commonly unsep- 

 tate, which spring from a spore lying in the 

 endosarc, and which stand in a semi-para- 

 sitic relation to the genus Amoeba. 



The facts which I submit in support of 

 this thesis are both morphological and 

 physiological. 



1. Morphological. — It may be remarked at 

 once that Dr. Leidy's text description and 

 plate delineations represent, with life-like 

 precision, the general features of the struc- 

 ture, and make it unnecessary to set forth 

 forth here what has already been done so 

 admirably. I mention only what he omitted 

 to notice or failed to see the exact signifi- 

 cance of. 



a. The single or tufted filaments arise in- 

 variably from a spore. See Figs. 3, 4, 5, 

 6, 10. In Dr. Leidy's Plate IX., Fig. 11, 

 there is a suggestion of this structure, but 

 the text reference to it shows that he did 

 not recognize the spore.* In the specimens 

 which I studied it was usually conspicuous, 

 though the structural continuity of spore 

 and filament could not always be made out, 

 even when the filaments were detached. 

 Cf. Figs. 3, 4 and 6. In this case, how- 

 ever, the spore came away with the fila- 

 ments. 



This would seem to be decisive of the 

 fungoid nature of the filaments. Leidy's 

 already quoted objection, viz., that the fila- 

 ments do not grow from a mycelium within 

 the body of the animal, becomes groundless 

 when it is seen that the filaments are them- 

 selves the branched mycelium resulting 

 from the germination of the spore. The 

 fact that the mycelium, instead of ramify- 

 ing through the protoplasmic mass, issues 

 at once into the water, suggests that this 



* Fresh-Water Ehizopods, p. 68. Cf. Proceed. 

 Acad. Nat. Sci. Phila., 1874, p. 78. 



fungus does not subsist at the expense of 

 the Amceha, but upon organic substances 

 dissolved in the water. Some of these are 

 doubtless contributed by the contractile 

 vacuole, which, as I observed, always lies 

 in the neighborhood of the filaments ; in at> • 

 least one case I saw it discharge its con- 

 tents among them. If this be true, we 

 may accordingly mention two advantages 

 which the fungus secures by its association 

 with the Ameeba : first, a food- supply in 

 the wastes of the AmcBha ; second, change 

 of location with consequent improvement of 

 ' pasturage.'* And so I have spoken of the 

 dependence as semi-parasitic. 



h. The structure of the filaments is that 

 of unseptate hyphfe, not that of jjseudopods. 

 An occasional septum at the origin of a 

 branch makes the pseudopod interpretation 

 impossible. It must be said, however, that 

 the characteristic mode of branching is pe- 

 culiar among the fungi. 



c. After separation from the Amceha the 

 filaments maintain in all respects their spe- 

 cific structure and relations. In some cases 

 I saw tufts of filaments, each with its spore, 

 come away from the host, for no apparent 

 reason, as it moved through the water. At 

 other times, by pressure upon the cover- 

 glass, the filaments were forcibly separated. 

 In all cases the filaments were unaffected 

 by the change, and the Ainceba showed no 

 sign of his loss in either his structure or his 

 movements. 



2. We may attend now to certain physio- 

 logical facts bearing upon the thesis of this 

 paper. 



a. As noted above, the form on which 

 these fascicled hyphse were found by Mr. 

 Archer in Ireland was Amoeba villosa. Mr. 

 Woodward informs me that the same is true 

 of his specimens, found, I presume, in the 

 neighborhood of London. If I have cor- 

 rectly interpreted Dr. Gruber, he found 



* Gruber (loc. cit. ) suggests the advantage of 

 oxygen supply from ingested algae. 



