284 Evans .— Vegetative Reproduction in Metzgeria . 
of cells, averaging about 0-15 mm. in diameter and measuring from six to 
eight cells across. Along the margin are scattered a few rudimentary hairs. 
The gemmae are set free by a splitting of the walls at the base (Fig. 9, C), 
leaving behind the single cell (or the two cells) cut off by the original 
Fig. 10. AI. crassipilis. A. A germinating gemma, x 80. B. Portion of a yonng thallus 
developed from a gemma, showing the first indications of a costa, x 80. c. Germination of 
a gemma with two apical cells, x 80. D. A germinating gemma, showing the young [thallus 
developed from the margin instead of from the apex. x 80. E. A germinating gemma, the young 
thallus showing indications of reversion. x8o. F. Portion of a young thallus with new marginal 
gemmae. x 80. 
horizontal wall. The cell thus left is lower than the neighbouring thallus 
cells, and the remains of the ruptured wall of the original projecting cell 
may often be demonstrated (Fig. 9, D and e). The two or three basal 
cells of the gemma become rounded off after separation and can usually be 
distinguished from the other marginal cells. 
