SPECIES OF CALLOPHYLLIS AND RllODYMENIA. 81 



Through the kindness of Prof. Sehmitz, who has allowed mo 

 to study some of his preparations of this species, I have seen 

 that the anatomical structure of the thallus is similar to that of 

 H. palmata, the typical JRkodymenia species*, viz. a thicker 

 centre or medullary layer of larger cells which are not surrounded 

 by small interstitial cells, but lie closely together (in the species 

 R. pertusa perhaps even more so than in the type B. palmata). 

 The cortical cells are arranged in more or less irregular order, 

 with the exception of the outer layer, which is distinctly at right 

 angles to the cortex ; the cells of the cortical layer are larger 

 towards the inner part of the thallus, and decrease in size towards 

 the cortical layer; so that the outermost layer consists of the 

 smallest cells which lie close together, forming a more or le*s 

 compact cortex. 



The cystocarp shows a similar resemblance to that of the 

 typical species of the genus, RJiodymenia palmata. It projects 

 on one side of the thallus, and possesses a fairly thick fruit-wall 

 of five or six cells in thickness arranged irregularly inwards. 

 At the bottom of the fruit-cavity is to be found the placenta 

 formed of numerous small cells closely packed together, and 

 lying on the medullary layer of large cells. From this placenta 

 the gonimoblast, of a more or less circular shape, is borne on an 

 elongated style-cell, and spreads upwards into the empty fruit- 

 cavity. 



This gonimoblast is composed of numerous pear-shaped lobes 

 which lie close together. The spores of these lobes become ripo 

 nearly at the same time. 



The ostiole is generally quite in the centre of the projecting 

 fruit-wall, and is similar to the ostioles of the kindred species. 



This structure shows that this is a true species of the genus 

 Mhodymenia. The other two species of the same group must 

 remain doubtful as to their true generic position until the 

 cystocarps have been found and described. 



III. 



In studying the structure of the above-mentioned specimens 

 of Callophyllis, I was induced to observe also the development 

 of the fruit; and though I cannot give a complete history of 



* Sehmitz, " Systcmatische Uebersicht der Gattungen der Floridcen," Flora, 

 Jahrg. 72(1880). p. 435. 



