GENUS ANTHOPHYSA. 2 7 I 



direct a manner as lia"d been intended. The damp growing-cell in which these 

 organisms were confined, unfortunately became dry during an absence of more 

 than a day's duration. Although everything contained in the cell was completely 

 desiccated, abundant traces were left, nevertheless, of what had taken place previous to 

 the evaporation of the water. At each spot which had been carefully noted as the 

 point of attachment of the quiescent or encysted monads, was a minute, dark brown, 

 striated, branching stem, corresponding in all ways with the characteristic pedicle 

 of AnthopJiysa vegetans. The process of drying up had necessarily removed every 

 trace of the animalcules whose presence would have still more satisfactorily esta- 

 blished the connection between the monadiform products of the original egg-like 

 cyst and the colonies of the species named ; the evidence of the branching and 

 striated stems was, however, so substantial as to leave little, if any, doubt of their 

 relationship. How this original ovate cyst, assuming that it belonged to Antho- 

 pJiysa vegetans, was originally produced, remains to be determined. Judging from 

 its comparatively large size it would appear to be most reasonable to surmise 

 that it was formed by the coalescence of an entire colony or spheroidal terminal 

 cluster of the flagelliferous monads, which after encystment broke up into abundant 

 smaller uniflagellate locomotive germs, which made their escape under the conditions 

 just related. A parallel fusion of numerous zooids succeeded by encystment and 

 breaking up of their united masses into numerous spore-like bodies, is afforded in 

 the life-history of the monad first described and figured by Messrs. Dallinger and 

 Drysdale, as the "Hooked Monad," and which finds a place in this volume under the 

 title oiHeteromita uncinafa. Phenomena closely identical are also presented in that 

 mode of multiplication among the sponge-monads manifested by the production 

 of the swarm-gemmules or so-called ciliated larvje described in Chapter V, 



Some slight additional testimony in favour of the above-suggested interpretation 

 of the developmental phenomena of AntJwphysa vegetans is afforded by the illustra- 

 tions of this species given in Stein's recently published work. Among his excellent 

 illustrations of this type — the more important of which are reproduced in PI. XVIII. of 

 this treatise — a representation is given (see Fig. 6) of a normally detached spheroidal 

 cluster or " coenobium," whose constituent monads have become separated from one 

 another, and protrude from their posterior regions tail-like pseudopodal prolongations. 

 At Figs. 7 and 8 of the same plate are represented similarly derived isolated monads 

 that have assumed a conspicuously amoebiform contour. In some instances, as 

 shown at Fig. 9, it would appear that these amoebiform zooids attached themselves 

 separately and lay the foundation of new colonies, but it would seem also highly 

 probable that under such condition they, in common with various other Flagellata, 

 coalesce together and produce sporocysts similar to the one just described. 



The highly distinctive longitudinally striate aspect of the branching stem oi A?itho- 

 pJiysa vegetans is not definitely indicated in any of Stein's figures, and it is further note- 

 worthy that the example selected by him as illustrating the normal stock-form of this 

 interesting species (see PI. XVIII. Fig. i) represents that lax and attenuate structural 

 type indicating either the absence of congenial nutriment, or that the colony has 

 outgrown its strength and lacks vital energy sufficient for the production of its 

 customarily erect and comparatively massive zoodendrium. De Fromentel, in his 

 ' Etudes sur les Microzoaires,' figures a like emaciated colony-stock. An almost 

 precisely parallel deviation from a normally erect to a lax and decumbent growth- 

 form, is afforded by the Peritrichous type, Epistylis flavicans. whose branched 

 zoodendrium, while stiff and erect in its earlier and most robust condition, presents 

 later on that loose and weakly structural form upon which Ehrenberg and other 

 earlier authorities, regarding it as a distinct variety, have conferred the separate 

 specific title of Epistylis grandis. In the original delineation of the species given by 

 O. F. Miiller, under the title of Volvox vegetans* reproduced at PI. XVII. Figs. 13 

 and 14, the more ordinary rigid and erect growth-form of the branching pedicle 

 is represented. Brightwell, in his ' Infusorial Fauna of Norfolk,' 1848, figures this 



' Animalcula Infusoria,' 1786. 



