300 EVANS. 



fertilization has taken place. The calyptra at maturity is clavate, 

 measuring about 1.2 mm. in length and 0.6 mm. in diameter in the 

 upper part, exclusive of the hairs. The latter are densely crowded 

 above the middle and more sparingly developed toward the base; 

 some of them attain a length 0.4 mm. 



On one of the specimens from Corral, No. 138, several capsules are 

 present and give an opportunity for describing the valves, our knowl- 

 edge of which in Metzgeria is still very incomplete. The mature 

 capsule is dark brown and oval, measuring about 0.6 mm. in length and 

 0.4 mm. in diameter. The valves, when spread out flat, measure 

 0.6X0.3 mm. and are composed, as is uniformly the case in Metzgeria, 

 of two layers of cells. Those of the outer layer (Fig. 7, A) are more or 

 less subject to variation but in the more typical cases extend length- 

 wise and are two or three times as long as broad, a valve being mostly 

 fourteen to sixteen cells across. The local thickenings of the cell- 

 walls are conspicuous and are largely (but not wholly) confined to the 

 inner longitudinal walls, that is, to the walls turned toward the 

 middle of the valve. The median wall thus shows two rows of thick- 

 enings, which alternate with one another, whereas each other longi- 

 tudinal wall shows only one such row. As a rule three or four thicken- 

 ings are present in each cell; they extend from the surface through 

 the thickness of the layer but are not prolonged on either tangential 

 wall. 



Although the cells of the inner layer (Fig. 7, B) do not exactly 

 correspond with those of the outer layer, they are of about the same 

 size and shape. With rare exceptions each cell shows from three to 

 six transverse bands of thickening on the inner tangential walls, these 

 bands being prolonged down the radial walls but not forming complete 

 rings. Sometimes, however, the bands are less developed and do 

 not extend wholly across the tangential walls, gradually fading out 

 toward the outer boundary of the cell. 



The spores are pale yellow, minutely punctulate, and 14-16 ix in 

 diameter. The elaters are mostly 0.3-0.4 mm. in length and 6 /x in 

 diameter in the middle, tapering gradually to the extremities. Each 

 one bears the usual broad band of thickening extending its entire 

 length. 



If the account of the capsule- valves as given above is compared 

 with the description of Andreas (1, p. 195) certain interesting differ- 

 ences become apparent. According to his statements the three rows 

 of cells of the outer layer that come next to the edge of the valve have 

 their thickenings definitely restricted to the inner longitudinal walls. 



