94 PROCEEDINGS OF SOCIETIES. 



Mr. Crowe drew attention to one or two instances of a curious, 

 as it were, arrested state of the conjugative process in Sfaiirastrum 

 mtspidatum. This, consisted in the united mass, formed from the 

 contents of the two parent cells, not becoming wholly withdrawn 

 from their cavities, but, in such partly-advanced stage, becoming 

 clothed with a cell-wall, this abnormally-formed (or precocious) 

 zygospore retaining more or less of a sub-cruciform or quadrate 

 figure, the four halves of the two parent cells being retained at the 

 angles. — this, induced partly by the common mucous envelope and 

 partly by a kind of expansion or dilatation of the angles of the mis- 

 shapen zygospore, projected into the cavities of the empty parent 

 segments and larger than the foramen. Thus the whole gave in 

 one aspect a pretty well-shaped figure of a Maltese cross — in 

 another presenting an elliptic outline surmounted at each end by 

 the empty segment of one of the parent cells, and then each of these 

 latter not unlike a "cocked hat" poised on each visible apex. 

 The whole had thus a curious and bizarre appearance, and to some 

 extent deceptive, especially until examined under a comparatively 

 high power ; but its singular shape seemed then quite obviously to 

 be produced by the united contents of the conjugating cells 

 becoming clothed with a wall before the common mass had as yet 

 become balled together into the typical orbicular figure. 



Mr. Archer exhibited examples of a plane or compressed variety 

 of Staurastrum vestitiim, that is, each segment possessing two arms 

 only — a companion thus to Dr. Barker's plane variety of Stauras- 

 trum graciJe, and thus bearing out Mr. Archer's view that such as 

 these are but accidental, though in no way abnormal, representatives 

 of certain species, not (at least on that account) distinct species in 

 themselves — for, in point of fact, examples two-armed on one seg- 

 ment, whilst three-armed on the other, were to be met with in the 

 present material ; but still in the We»tmeath pools the plane form 

 of Staurastrum graciJe is the pervading one. 



Mr. Archer showed an example, dyed by carmine solution, of the 

 large " Amoeha-actinosphcerium-Uke " llhizopod, of which clearly- 

 remarkable form he had exhibited living examples at the Club 

 Meeting of 29th Sept., 1S70 (' Quart. Journ. Micros. Sci.,' vol. xi, s. 

 s., p. 101, which please see), and which he thought would prove to 

 be identical with the rhizopod forming the type of Grenacher's new 

 genus Pelobius. As he (Mr. Archer) had given a brief record 

 already {Joe. cit.) of the particular rhizopod he at least had in 

 view, which might, he hoped, serve to identify it if met with in this 

 country bj^ others, it would be unnecessary to recapitulate in any 

 way on the present occasion, especially as it is to be expected that 

 Dr. Grenacher's promised description, with plate, of his Pelobius 

 may ere long make its appearance ; for indeed, until then, the 

 identity of that with the present could not be considered as at all 

 certain. But meantime Mr. Archer ventured to hope the present 

 fugitive preparation, showing the numerous nuclei (or capsules ?), 

 highly dyed by the solution, would be viewed by the meeting with 

 a certain amount of interest. 



