73 



f. grandifrons Fosl. mscr. 



f. ramis superioribus fasciculos minutos, confertos, e ramis 

 brevissimis compositos formantibus. Tab. 13. 



Description of the spedes. This plant is much varying, and, 

 in the sense here tåken, it perhaps includes more than one species, 

 but nearly all the specimens that I have seen are sterile and, there- 

 fore, the limits difficult to draw. Like the preceding it in a younger 

 stage also has a nearly spherical shape, but it apparently sooner 

 becomes subhemispherical, at length hollovv and assumes a cup- 

 shaped appearance. It attains a diameter of at least 50 cm., fre- 

 quently, however, smaller, the form grandifrons in general larger 

 than the typical one, but also the latter attains a considerable size. 

 The colour accords with that of L. dimorphum, in winter probably 

 also getting as dark as this species, however, in summer now and 

 then with a stronger colour than specimens of the named species 

 at the sa.me season, but apparently only depending on the locality 

 where it grows. I have even seen specimens with a yellowish- 

 green colour, thus in this respect much varying. The species ap- 

 parently always develops itself freely on the bottom. Although 

 often growing on stony bottom I never met with it fastened to or 

 encompassing stones or other hard objects. The frond is some- 

 what irregularly branched in a subdichotomous manner, with axes 

 of at least four orders. The branch-systems at first issue in all 

 directions from the centre of the frond, and the solid central mass 

 appears always to be insignificant. In a more or less advanced 

 stage the central or inner portions by and by disappear, which, 

 however, may be forced by attack of animals, the peripherical 

 portion developed in a more horizontal direction, and the plant 

 opening itself in the part turning towards the bottom, seldom in 

 the upper part, at length assuming a frequently depressed cup- 

 shaped form, rubbed in the part turned downwards, with the inter- 

 walls between the branch-systems visible from this side, most often 

 subcircular in circumference, and then only about 2 cm. thick. 

 The figure on pl. 11 represents an old but fragmentary specimen, 

 the longest diameter about 32 cm., depressed cup-shaped and rub- 

 bed in the part that has turned towards the bottom, here burdened 



