Meyen's Report for 1839 on Physiological Botany. 401 



circumference of the spore-cuticle. The remaining observa- 

 tions agree with the results of former ones, and are already 

 known. A series of excellent delineations accompanies the 

 paper. M. Mohl then proceeds to compare his view of the 

 formation of the spores with that of M. de Mirbel. Accord- 

 ing to the view of the latter, the formation of the spores 

 depends principally on the primitive cell, for the contents 

 are divided mechanically into four parts by the projecting 

 partitions. According to M. Mohl's earlier idea, the develop- 

 ment of four spores in a primitive cell depends solely on 

 the organic change of the contents ; but his late observations 

 on Anthoceros appear to support an intermediate view, for the 

 development of the partitions is produced by that of the con- 

 tents of the primitive cell. Finally, M. Mohl endeavours to 

 show that no great importance must be attributed to the cir- 

 cumstance of the four divisions of the primitive cell communi- 

 cating with each other or not, and that we must not consider 

 this process as a characteristic distinction between the primi- 

 tive cells of the spores and those of the pollen-grains. Tn An- 

 thoceros Icevis M. Mohl could not observe this division; in 

 Anth. j}U7ictatus he thinks he saw it, and also in Jungermannia 

 epiphylla, but not in Riccia glauca. 1 have published the re- 

 sults of some new observations on the formation of the spores 

 oi Amur a ping ids. which may be regarded as a sequel to those 

 spoken of in the third volume of my * Physiology' (Berhn, 

 1839). In the first stages of the fruit there were found only 

 very tender long cells, which were imbedded in a gummy 

 matter ; these cells enlarged, and at length lay close to each 

 other, and at a later period it was seen that from these at 

 first perfectly homogeneous cells, not only the elaters, but 

 also the spores, were formed ; some become elaters, and 

 others undergo a series of changes, until at length the spores 

 are produced. The cell out of whose division four spores 

 are always produced, I have called primitive spore (Mutter- 

 spore), and of these primitive spores, three, four, or even five 

 are formed in each tubular cell ; whilst those neighbouring 

 cells which afterwards produce the formation-tunic retain 

 their granular contents unchanged, until the spores are per- 

 fectly developed. As soon as the primitive spores are formed, 

 a gelatinous membrane appears at their peripheiy ; this has 

 been called primitive cell ; 1 designate it as formation-tunic or 

 skin (Bildungsbriille). Sometime afterwards I observed two, 

 three, or even four primitive spores enclosed in their forma- 

 tion-tunics, connected with each other in a row, and occupy- 

 ing the place of the original tubular cell, but from want of 

 material I could not determine whether these formation- 

 Ann. ^- Mag. N. Hist. Vol. vii. 2 D 



