2 8 





II. 



I osl. f. tualemis. 



Part of a n I a branch; X 72. 



I'hc cells are partly of the same of the last mentioned form, partly throughout 



maller, partly - and as a genera) thing — ■ longer, 

 the hypothallic ones sometimes being up to 30 <j.. long. Such 

 is also the case with f. brac h ia la . the cells of which are 

 also partly a little longer throughout than those off. tualensis, 

 partly, however, quite like the latter in structure. On the 

 other hand the structure of f. brachiata is even approaching 

 to that of Lithothamnion erubescens with more regular cells 

 and thinner walls, than usual in any form of L. australe. 

 Also the structure of f. minutula is rather varying and shows 

 conformity partly with that of f. tualensis, partly with that 

 of f. brachiata. 



As to structure, L. a?tstrale thus presents about the 

 same variety as L. fruticulosum, though perhaps in a less 

 degree, as in the latter a considerable difference is prevailing 

 between specimens crustily spread with short branches and branched specimens which have lain 



free on the bottom. The cells of the latter are always longer than 

 those of the former, and in the Adriatic f. ramulosa always lying 

 free on the bottom the hypothallic cells are generally even longer 

 than in a much branchine f. crassiuscula. and can attain a leneth of 

 up to about 30 u. L. australe is, therefore, most closely connected 

 with branched forms of the said species. 



The varying habit and irregular development above mentioned 

 due to extraneous objects, of course appear also in sections of the 

 plant. But, on the other hand, irregular developments in the structure 

 are often to be seen without any apparent external alteration, being 

 however also in such cases caused by damage in some way or 

 other, or by delicate extraneous objects attached to the plant (Fig. 1 2). 

 The latter represents a small part of a median section of a branch 

 of a rather coarse specimen which comes nearest to f. ubiana. Here 

 a part of the branch has been damaged or burdened with delicate 

 foreign bodies. A new and even marked coaxial hypothallium is 

 then formeel, resembling the said layer of tissue in several crustlike 

 species. This hypothallium issues from the surrounding undamaged 

 parts of the perithallic layer towards the centre of the damaged 

 part. When this part has been covered with the new hypothallium, 

 the latter sends forth perithallic rows in connection with new thickening 



Fosl. f. 1 ■ , r 1 1 1 1-11 -1 1 



Qch layers m the parts 01 the branch which have remained unnurt. 



As mentioned above, I have met with very few reproductive 

 organs in L. australe. Thus only a couple of specimens off. tualensis 

 i with a few conceptacles of sporangia. These specimens were taken in the month 



men, with a new- 

 ithallium covi 



■ 72. 



