IV. 



THE ANTIIOCEROTES 



141 



simultaneously between the four nuclei dividing the mother cell 

 into four tetrahedral cells, — the young spores. The wall of the 

 mother cell becomes thicker, and in the later stages swells up 

 on being placed in water, so that it interferes a good deal wdth 

 the study of the spores in the fresh condition. As the spores 

 ripen they develop a thick exospore, which is yellow in colour 

 and irregularly thickened in A. Pcarsoni, and in A. fiisiformis 

 black and covered wnth small tubercles. The chlorophyll disap- 

 pears and the spore becomes filled with oil and other food 

 materials. The spores remain together until nearly ripe. The 

 elaters, if this name can properly be applied to the sterile cells, 

 at maturity consist of 



simple or branching B. "^• 



rows of cells, which in 

 some cases arise from 

 the division of a single 

 one; but more com- 

 monly, at least in A. 

 Pcarsoni, where they 

 branch, it is probable 

 that they are to be 

 looked upon as merely 

 fragments of the more 

 or less continuoiis net- 

 work of sterile cells. 

 The contents mainly 

 disappear from the 

 older elaters, and their 

 walls become thick and 

 in colour like the w^all 



of the spores. In A. fiisiformis they are longer and more 

 symmetrical than in A. Icuvis, and in one group of the genus, 

 according to Gottsche (2), the elaters, which consist of a row 

 of five to six cells, have a distinct spiral band as in Dendroccros. 

 Leitgeb thinks, however, that this group is more nearly related 

 to the latter genus than to Anthoceros proper, inasmuch as in 

 addition to the peculiar elaters the epidermis of the capsule has 

 no stomata, w^hicli are always present in typical species of 

 Anthoceros. 



If the epidermis from the young capsule is examined it is 

 spen to be composed of elongated narrow cells much like those 



D 



Fig. 73. — Spore division in A. fusiformis; optical 

 sections of living cells, X6oo. 



