GRAF ZU SOLMS-LAUEACII— MONOGliAPlI OF THE ACETABULAllIE/E. 11 



of the enclosed spore possesses already its own cuticle-like outer lamella exactly as in 

 Acetahularia, thus appearing completely closed externally. AVe should have to assume 

 that tliis lamella gradually succumhs to tlie transformation into slime and is again 

 renewed from the layers heneath, which is indeed the less impossihle since the membrane 

 in question does not represent a cuticle in the chemical sense of the word. We shall 

 return to this point in describing the spore-structure of the genus Ilalicoryne. The 

 tracing of the mode of development of the sporangial ray, which alone could give us 

 more information on this point, was impossible owing to the state of the material. 



The fossil form described by Andrussow as Acetahularia miocenica, Andr., whicli occurs, 

 forming on rocks, in the Crimea, south of Sebastopol, in the ravine of Karanj, may be put 

 with the genus Acicularia. But in this form there are not merely the spore-containing 

 spicula?, but whole caps, and their parts are preserved. From Andrussow's [2] descri|)tion 

 and figure I had thought of putting it into Jcioularia even before I had received several 

 fragments through the kindness of the author. The examination of this certainly 

 scanty material lias only confirmed me in my opinion. In fact it agrees with Acetahularia 

 or Acicularia in external conformation as well as in its double corona, but whether the 

 corona exhibits the characters of Acetahulnm or Acetahuloides could not be determined 

 from my material. The extraordinary strength of the chamber partition- walls is very 

 striking, and it gives great consistency and hardness to the whole fossil. This is not 

 shown in Andrussow's somewhat diagrammatic woodcut. Each sporangial ray encloses a 

 free spicula formed like it and bearing the spore-cavities in four rows, of which two lie 

 near the upper and two near the lower membrane, while in the middle and towards 

 the chamber partition-walls homogeneous lime prevails. (Compare the surface view of 

 the chambers containing the spiculc3e, Plate III. fig. 13.) Round each spore-cavity there 

 is a circular zone which stands out, when viewed in a reflected light, through its 

 white colour against the central mass of the spicula, though a sharp contour is not visible. 

 The calcification does not appear from Andrussow's statements to be so complete in all 

 cases, for he says (§ 78) : " But sometimes the calcification appears to have gone farther, so 

 that almost the whole cavity of the radial chambers is filled with lime and only small 

 round holes remain corresponding to the cells. At least certain of the specimens from 

 the Karanj ravine indicate this, and somewhat rubbed portions of such specimens show 

 a certain likeness to the so-called Acicularia from the Paris Eocene." Such, at any rate, 

 are the specimens I have seen. Nevertheless it is not to be doubted that the spores 

 when the plant was alive were united in calcified spicula3, perhaps of loose porous 

 consistency. In the fossilization of spore-bearing uncalcitled Acetahularia chambers the 

 spores would probably be destroyed, and would certainly not be preserved with so sharp a 

 contour of the interior and in so characteristic and regular position. Andrussow himself 

 assumed a calcification of the living spore-wall. He says [2, p. 79] : — " Our alga is 

 generally more calcified than the known Acetabular ia;, and it is still more distinguished 

 from them by the presence of cells in the chambers, which has not been observed in any of 

 the living AcetahulariecB. This circumstance, however, appears to me to be insufficient to 

 warrant the removal of this alga to a separate genus. We know, indeed, that the radial 

 chambers in a ripe state are filled with spores arranged, according to Woronin, in a spiral 



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