35 6 NOTES AND COMMENTS [may 1899 



focus from those at the other. There is consequently no need to assume 

 that the two layers of waves are due to two striated membranes. 



Again, the question of undulating membrane or row of cilia is of 

 no real importance ; in a large number of cases undulating membranes 

 have been proved to be simply agglutinated cilia, often separable on 

 death. Of such nature are the comb-plates of Ctenophora, the mem- 

 branellae of the disc in some liotifers, and those of Ciliata. The 

 distinction is not a strong one. 



The details given are interesting and well put. 



Plant Embryology. 



In the March issue of the Botanical Gazette, Prof. I). H. Campbell 

 makes a further contribution to the embryology of the monocotyledons. 

 A study of the embryo-sac of Sparganium reveals an enormous develop- 

 ment of the antipodal cells after fertilization of the egg-cell. Hofmeister 

 many years ago called attention to the conspicuous antipodal cells of 

 certain grasses, and showed that the number might exceed the three 

 usually found in angiosperms ; and more recently Westermaier has 

 pointed out that in the maize and others this exaggerated group of 

 antipodal cells functions as endosperm in early stages of development 

 of the embryo. Ivoernicke mentions thirty -six as an outside number, 

 but Campbell finds in Sparganium more than a hundred cells, or in 

 older stages a hundred and fifty. He suggests that these resemblances 

 may imply a closer affinity than has hitherto been supposed between 

 Sparganium and the grasses. 



Another plant studied was Lysichiton kamtschatcense, an aroid inhabit- 

 ing North-East Asia and the Pacific coast of North America. Here 

 again the antipodal cells show an unusual development but in size 

 rather than number. There are probably never more than ten, but they 

 become extremely large and the nuclei reach enormous proportions. 

 Their appearance is quite different from those of Sparganium, and indeed 

 of any other known angiosperm ; they most resemble certain Compositae 

 such as Senecio and Aster, in which numerous antipodal cells have 

 been described, and also a continuous endosperm, another feature of the 

 embryology of Lysichiton. We cannot, however, regard these resem- 

 blances as indicating any systematic affinity. Professor Campbell has 

 studied the embryology of other members of the order Aroideae and 

 hopes soon to publish a full account of the results of his work. 



