141 



■ceptaculis cystocarpiferis convexiusculis vel fere hemisphæricis, dia- 

 metro 250 — 300 \x\ sporangiis quaternas sporas foventibus, 120— 

 135 p. longis, 45 — 60 ;j. latis. Tab. 19, fig. 10. 



Description of the spedes. The plant forms incrustations on 

 other and branched Lithothamnia. The crust elings closely and 

 firmly to its substratum, and is about 0.5—1 mm. thick, frequently 

 surrounding nearly all the branches of the host plant. The nature 

 of the surface is determined by that of the substratum. If this is 

 smooth, the crust is also smooth and feebly shining especially 

 "when young. Older crusts partly are very finely rugged and 

 squamellate by growing over small extraneous objects, or on ac- 

 count of the shape of the conceptacles, or scaly thickenings, partly 

 nearly smooth, with indistinct concentric and radiating striæ. The 

 brim is thin, feebly concentric zonated, and the margin shallowly 

 crenate with rounded lobes. The colour is a purplish pink very 

 much like that of L. polymorphum, only lighter than is usual in 

 the latter. 



The lovver, co-axil system of the frond is feebly developed 

 and in the fragment examined scarcely perceptible on a section. 

 In the upper thickeningdayer the cells are smaller than those of 

 the nearly allied L. polymorphum, nearly squarish or rectangular, 

 7 — 9 y- long and 5 — 7 p. thick. Overgrown conceptacles are more 

 or less numerous, occasionally having been filled with local forma- 

 rtions of tissue. 



The conceptacles of sporangia in their development and even 

 as to the appearance closely resemble those in L. polymorphum. 

 They, however, are frequently larger, the visible part of the roof 

 itself about 150 — 200 fi in diameter, including the border 300 — 

 •350 /a, and is intersected with 40 — 50 muciferous canals, which 

 are smaller than those in the named species. At maturity the roof 

 gets more frequently fully dissolved than in the latter, seldom also 

 a part of the border, leaving a distinct hole. The sporangia are 

 four-parted, 120—135 <j- long and 45 — 60 />- broad. 



What I think to be the conceptacles of cystocarps appear on 

 the same individual bearing those of sporangia. They also resemble 

 .the probably similar organs in L. polymorphum, in a certain state, 



