On the Morphology and Physiology of the Cell. 211 



Hseckel has figured one of the Monera — his Protomyxa 

 aurantiaca, which forms similar cell fusions. One or two 

 similar Ehizopocls have also been observed, and my own 

 observations have shown that this tendency to union, appa- 

 rently unimportant and rare, is really one of the best 

 marked tendencies of the amceboid cell. For the corpuscles 

 of invertebrates taken from various groups — urchins, star- 

 fishes, bivalves, gasteropods, worms, or crustaceans, all form 

 Plasmodia. The phenomenon can be best observed in 

 the sea urchin, by suspending a drop of the perivisceral 

 fluid from the under surface of a cover-glass placed upon a 

 glass ring, of which the under side should be oiled to prevent 

 evaporation. A little carmine or ultramarine may with 

 advantage be added. Union takes place only between the 

 finely granular corpuscles, which soon form an immense 

 amoeboid mass, which differentiates into granular endosarc 

 and hyaline ectosarc, the latter of which sends out pseudo- 

 podia of extraordinary length and activity, which readily 

 absorb any free corpuscles of the finely granular sort, — the 

 coarsely granular corpuscles, like the foreign pigment 

 granules, being simply taken into the interior of the 

 mass.* 



12. In my former papers on this subject I have com- 

 pared these Plasmodia to such Ehizopods as Microgromia 

 socicdis (Hertw.),-|- Piccphidioijhrys, etc., in Avhich several 

 constituent units are united by bridges of protoplasm. The 

 well-known structure of Vol vox, the beautiful Moneron, 

 Monohia conjluens, recently figured by Schneider, ;]: and 

 the remarkable recent announcement of Frommanng that 

 the meristem cells of Draccena, Rhododendron, etc., are in 

 direct protoplasmic continuity by means of delicate filaments 

 passing through foramina in the cellulose wall, however, 

 when viewed together with the case of such Ehizopods, fur- 



* Obs. s. 1. Fluide Perivisceral des Oursins, Arch, d, Zool., Exp. YIII. ; On 

 the Coalescence of Amceboid Cells, etc. (Proc. Roy. Soc. Lend., No. 202, 18S0). 



t R. Hertwig, Ueb. Microgromia socicdis, etc., Arch. f. ]\Iikr. Anat. PhI. 

 and Taf. 1, 1874. 



X Arch. d. ZooL, Exp., 1880. 



§ Beobacht. lib. Structur, etc. d. Pflanzenzelle. Jena, 1880. 



