ZPOLOGY AND BOTANY, MICROSCOPY. ETC. 189 



BOTANY. 



(Under the direction of A. B. Rendle, M.A., D.Sc, P.R.S., F.L.S.) 



GENERAL, 



Including the Anatomy and Physiology of Seed Plants. 



Cytology, 

 Including: Cell-Contents. 



Morphological Constitution of Cytoplasm of Plant-cells. — A. 

 GuiLLiERMOND {Rev. Geiur. ScL, 11)21. 32, 133-40, figs.). Contrary 

 to the opinion expressed by many writers, the author maintains that, 

 there is no essential difference between the structure of the animal- 

 and plant-cell ; both in morphological and chemical structure the chon- 

 driome of the plant-cell is the equivalent of that of the animal-cell, 

 but in chlorophyll-bearing plants the chondriome is affected by photo- 

 synthesis. 



Fig. I. — Animal-cell (living), m, mitochondrias ; v, vacuoles. 



Those authors who differ from this view have apparently based their 

 opinions upon either a too exclusive study of Phanerogams — in which 

 only one variety of mitochondrias can be(1istinguished in the embryonic 

 stage, and have therefore concluded that the plastids arise from the 

 undifferentiated mitochondrias of the meristem — or, having confined 

 their attention to the Muscinea3, have assigned to the plastids a signifi- 

 cance and nature apart from that of the mitochondrias. 



The present work shows that there are two varieties of mitochondrias. 

 [n Phanerogams they are of the same form and dimensions in the 

 embryonic cells, and the difference does not become visible until the 

 adult stages, where photosynthesis is in active progress. In the Alg« 

 and Muscinea3, where photosynthesis is continued through the entire 

 life-history of the plant, the two forms of mitochondrias are easdy 

 distinguishable from the earliest stages of the embryo. In ferns they 



