No. 460.] STUDIES ON PLANT CELL. V. 223 



tory of smut or rust. One of the best discussions of cell 

 fusions in the fungi is that in Harper's paper ('99 a), noted 

 above. 



Although most of the protoplasmic connections in higher 

 plants are of the fibrillar character there are some notable illus- 

 trations of broad openings between cells, even more conspicuous 

 than those in the red algae. Such may be found in the pores of 

 sieve-plates traversed in their early stages by strands of proto- 

 plasm that later disappear, and even better illustrations are the 

 unions between cells composing laticiferous vessels. But the 

 most interesting conditions are those associated with the nutri- 

 tion of the eggs of certain cycads. Goroschankin ('83) first 

 noted for the cycads pores or canals in the egg-wall of Ceratoza- 

 mia and described communications between the protoplasm of 

 the enveloping cells of the jacket and the egg. The subject is 

 closely associated with the explanation of the proteid vacuoles in 

 the eggs of gymnosperms which Arnoldi believed to be nuclei 

 that had migrated from the surrounding cells. The conclusions 

 of Arnoldi have not been sustained (see Sec. Ill, Amer. Nat., vol. 

 38, pp. 591, 592, 1904) but the presence of pores in the egg-wall 

 of gymnosperms is likely to prove very general with further 

 investigation. A recent paper by Miss Isabel Smith (:O4) gives 

 an account of haustoria-like processes from the egg of Zamia 

 which pass through the pores of the egg-wall into the cells of 

 the jacket, where they are in direct contact with its -protoplasm. 

 These pseudopodia-like processes of the egg apparently absorb 

 material from the cells of the jacket as is indicated by the char- 

 acter of their staining and the streaming movement towards 

 them of the protoplasm in the jacket cells. The relation of the 

 plasma membrane of the processes from the egg to that of the 

 jacket cells is not clear but probably they are merely in contact 

 and not in open communication. The ovules of cycads seem to 

 offer an especially favorable subject for the study of pore forma- 

 tion and the intimacy of protoplasmic connections between cells. 



It seems very clear that the cytoplasmic connections in the 

 Rhodophyceae, Volvox, fungi, and between the egg and jacket 

 cells of cycads involve very much more substance than is gen- 

 erally present in the delicate fibrillae of higher plants. Meyer 



