NOTES AND MEMORANDA. -^51 



abdomen is always free from the parasite. The further development 

 has been observed in both German and American examples, and con- 

 sists of a separation of the contents in the largest diameter of the cell, 

 and the formation of three or more daughter-cells ; but the origin of 

 the amoeba-like cells has not yet been observed. 



Cryptogamia Vascularia. 



Germination of the Schizaeaceae. — This interesting and singular 

 family of Ferns has been made a subject of careful invt stigation by 

 Bauke,* as far as concerns the structure of the prothallium and its 

 development from the spore ; his observations having been made 

 chiefly on Aneimia PhylUtidis, collina, and cheilantlwides, and Mohria 

 caffrorum. The following is a summary of his conclusions :— 



1. In all the genera examined, Schiza3a, Lygodium, Aneimia, and 

 Mohria, the spores are of a tetrahedral form. 



2. In Aneimia and Mohria, the exospore is invariably furnished 

 with characteristic ridges, which are either smooth or covered with 

 conical protuberances. 



3. The germination of the spore of Aneimia and Mohria does not 

 differ essentially from that of the Polypodiaceae and Cyatheaccaj, 

 except that the filament which is the first result of germination 

 develops into the plate of cells which constitutes the protliallium, by 

 the formation of longitudinal walls by the other cells of the filament, 

 at the same time that this takes place in the apical cell, or even 

 earlier. 



4. The apical cell of the filament divides longitudinally into two 

 more or less unequal segments. One of these becomes a plate of 

 cells increasing by marginal gi-owth. The other, usually the larger 

 one, is either distinctly marked as a wedge-shaped apical cell (Mohria), 

 in which septa arise inclined alternately to the right and left ; or 

 (Aneimia) several parallel septa are formed at right angles to the first 

 division-wall, commencing from below upwards. Even where there 

 was a distinct ajiical cell, it was not observed to become segmented 

 more than three times. 



5. In the first segment-cell of the apical cell formed in the last- 

 named manner, there is usually produced, after a time, a marginal cell 

 of characteristic form, which grows in the direction parallel to the 

 margin of the prothallium, and becomes divided by transverse septa. 

 This is the origin of the " cushion " of the prothallium. 



6. Independently of this lateral row of cells, which ultimately 

 becomes the cushion, the plate of cells increases by ordinary marginal 

 growth, advancing in a direction at right angles to the margin. This 

 proceeds actively, so that ultimately the lateral row of cells is 

 removed to a considerable distance from the base of the prothallium. 



7. At the time of the formation of the cushion, the form of the 

 prothallium is, in Aneimia, more or less distinctly reniform, the 

 lateral row of cells lying always on the concave side ; in Mohria it is 

 at first broadly spathulate, ultimately roundish. 



8. In Mohria, and sometimes in Aneimia, the cells of the lateral 



* Piiiigshcim's ' Jalirb. f. wiss. Bot.,' xi. (187S) 603. 



2 G 2 



