30 M. FOSLIE. [1899 



length form both fiahellata and other apparently characteristic forms. 

 The said formation is also to be found in crust-complexes of f. 

 Harveyi as vvell as f. angidata. Besides they are to be seen in 

 Ph. polymorphum, L. varians, and other spedes, but they are 

 only due to quite local conditions. The form subdichotoma is no- 

 thing more than f. angulata, and f. lahyrintliica old and in part 

 worn specimens. I have at least specimens resembling fig. 7 1. c. 

 of the latter, and they are in my opinion not at all to be consi- 

 dered as a separate form. Cp. Harv. Phyc. Brit. pl. 345, fig. 2, 

 i. Harveyi, which when old also assume the same shape. Ifsuch 

 are to be maintained, the recording of forms not only in this spe- 

 des but in the calcareous algæ at all would be so to speek endless. 



Lithophyllum fasciculatum (Lam.) Fosl. 



List of Lith. p. 10 ; iMillepora lasciculata Lam. An. s. vert. 2, 203 (ed. 2, p. 311) 



f. incrassata Fosl. 



On some Lith. p. 8. 



Melobesia fasciculata Harv. Phyc. Brit. pl. 74,. fig. 1. 



f. divaricata Fosl. mscr. 

 f. compressa Fosl. mscr. 

 f. eunana Fosl. 



Lithoph3dlum calcareum f. eunana Fosl. Some new or er. Lith. p. 15. 



How the calcareous algæ described by Lamarck as well as 

 some of those recorded by Harvey were to be understood has 

 often amounted to mere conjecture, partly because the descriptions 

 are rather scanty partly owing to the fact, that specimens from 

 different collections considered to belong to the one or other of 

 the spedes almost constantly have been sterile. Therefore, I took 

 the opportunity last spring to visit Roundstone on the west coast 

 of Ireland,^) where especially those critical spedes described by 

 Harvey have been collected. Thanks to the valuable company 

 of the Irish algologue Mr. Henry Hanna, facilitited by the kind- 

 ness of Prof. T. Johnson, I was so successful as to find most 

 probably at least one of the localities where M'Calla collected 



1) M. Foslie. A Visit to Roundstone in April. The Irish Naturalist, Vol. 

 Vin. 1899. 



