GEAF ZU SOLMS-LAUBACH— MOXOGll.VPH OF THE ACETABULARIE^. S 



laterally, and separated from the corresponding vestibule by a wall perforated in the 

 middle. Each one of these chambers consists of the basal portion, which bears a segment 

 of the corona superior and inferior, and runs out between both in the direction of the 

 radius into the sporangial ray. In Aceiabularla medlterranea there is no sharp limit 

 between basal portion and sporangial ray *, and both pass imperceptibly into each other 

 with an open lumen. But we shall see that this varies in allied forms, as may be seen 

 in the description of A. Peniculus. Characteristic of our species is the firm union of 

 the radial chambers already described ; it extends to all parts of them and reaches the 

 outermost margin, so that this appears as exactly circular as if cut out. The upper 

 corona is bounded on the outer side by a simple circular line ; in the lower the single 

 chambers bulge somewhat outwards, so as to give a wavy contour, which is added to by 

 the unusual thickening of the sections of the membrane f. 



In the ripe cap-bearing shoot the whole contents of the disc are used in the formation ol" 

 the egg-shaped spores, the peculiar formation of the membrane of which was represented 

 more correctly by de Bary and Strasburger than by Woronin. At one pole of the spore 

 the circular lid, which resembles a cone-valve inserted into the membrane from within, 

 is situated as in Neomeris ; its contour lines on both sides in an optical section of the 

 spore consequently converge a little outward. De Bary states correctly that the moderately 

 thick spore-membrane shows stratification, and consists of an outer thicker layer and an 

 inner thinner one of different capability of swelling up. He has established that both 

 layers are formed of cellulose, easily rendered blue and completely soluble in SO^H^, but 

 that on the surface of the spore there is found a tender cuticle-like pellicle, which sbiins 

 yellow with iodine and withstands sulphuric acid, but remains over after treatment 

 of the spore with concentrated acid in the form of a crumpled sac, when the whole 

 internal portion has been completely destroyed. There Avill be a farther op2)ortunity, in 

 describing the genera Chalmasia and Halicoryne, of returning to the very complicated 

 and peculiar structure of the membrane of the spores of Acetabulariem, since the spore- 

 membranes of these genera are much better adapted to investigation than those of 

 species of Aoetahularia on account of their greater thickness. 



Woronin had already observed this cuticle-like lamella, and he states that it is the 

 first thin membrane which the primordial spore forms on its surface. The cellulose 

 layers are consequently differentiated immediately afterwards as the second proper cell- 

 membrane. This point, as well as the development generally, deserves fresh investigation, 

 which ought to be carried out under conditions of time and place unfortunately 

 impossible for me, since they involve the summer months. JS^evertheless, I will now 

 briefly indicate the points for such revision and the question concerning it, in order that 

 other botanists, of Italy or the south of France, who always have access to the plants, 

 may have their attention drawn to them. According to Woronin there appear in the 



* The lumen of the latter is only somewhat narrowed towards the point of contact. 



t Woronin's figures, in Ann. Sc. Nat. ser. 4, tome xvi, pi. 9, are, so far as they are concerned with the 

 structure of the cap, somewhat diagrammatic, but in the main correct. His pi. 9. fig. 4 shows the central opening 

 in the membrane dividing vestibule from ray as too wide, and this division itself as a simple fold of the common 

 membrane. Compare the figure in this memoir, Plate I. figs. 7, 8. 



b2 



