M. FOSLIE. [1905 



4. Phymatolithon compactum (Kjellm.) Fosl. mscr. 



Lithothamnion compactum Kjellm. N. Ish. Algfl. (1883), p. 132, t. 6, fig. S— 12! 



f. typica. 



Descr. Kjellm. 1. c. Lithothamnion circumscriptum 3 validum Rosenv. Gronl. 

 Havalg. (1893), p. 103, fig. 3! Lithothamnion compactum Fosl. Norw. Lithoth. 

 (1895), p. 103, t. 19, fig. 1—4; Saund. Alg. Harr. Alaska Exp. (1901), p. 442! 

 Clathromorphum compactum Fosl. Syst. Surv. Lithoth. (1898), p. 4, Rev. Syst. Surv. 

 Melob. (1900), p. 10; Jonss. Mar. Alg. Icel. I (1901), p. 154! Setch. and Gardn. 

 Alg. Northw. Amer. (1903), p. 357! De Toni, Syll. Alg. IV (1905), p. 1726. 



f. testacea Fosl. 



Rev. Syst. Surv. Melob. (1900), p. 10; Lithothamnion testaceum Fosl. Norw. 

 Lithoth. (1895), p. 107, t. 19, fig. 5 — 9; Clathromorphum testaceum Fosl. List 

 Lithoth. (1898), p. 8. Non Lithothamnion testaceum Heydr. Lithoth. Helgol. (1900), 

 p. 77, t. II, fig. 16 (= Phymatolithon polymorphum) ! 



f. circumscripta (Stromf.) Fosl. mscr. 



Lithothamnion circumscriptum Stromf. Aigveg. Isl. (1886), p. 20, t. I, .fig. 4 — 8; 

 Fosl. Contrib. I (1890), p. 9, II (1891), p. 10, t. 3, fig. 8; Lithothamnion circum- 

 scriptum a areolatum Rosenv. Gronl. Havalg. (1893), p. 774! L. circumscriptum 

 Fosl. Norw. Lithoth. (1895), p. 132; Rosenv. Deux. Mem. Alg. Mar. Gronl. (1898), 

 p. 13! Clathromorphum circumscriptum Fosl. Rev. Syst. Surv. Melob. (1898, p. 5, 

 Rev. Syst. Surv. Melob. (1900), p. 10; Jonss. Mar. Alg. Icel. I (1901), p. 154! 

 Saund. Alg. Harr. Alaska Exp. (1901), p. 442! Borg. Mar. Alg. Fasroes (1902), 

 p. 400? Setch. and Gardn. Alg. Northw. Amer. (1903), p. 357! De Toni, Syll. 

 Alg. IV (1905), p. 1728. 



f. coalescens Fosl mscr. 



Lithothamnion coalescens Fosl. Norw. Lithoth. (1895), p. 134, t. 19, fig. 15—20; 

 Clathromorphum coalescens Fosl. List Lithoth. (1898), p. 8. 



Syn: Lithothamnion polymorphum Kjellm. Algenveg. Murm. Meer. (1877), 

 p. 8; Farl. Mar. Alg. New Engl. (1881), p. 182, partim! 



Lithothamnion durum Kjellm. Beringh. Algfl. (1880), p. 22, saltern pro parte! 



Lithothamnion scabriusculum Fosl. Norw. Lithoth. (1895), p. 142, t. 22, fig. 9, 

 De Toni, Syll. Alg. IV (1905), p. 1758? 



Lithothamnion evanescens Fosl. Norw. Lithoth. (1895), p. 137, t. 22, fig. 6 — 8, 

 partim, De Toni, Syll. Alg. 1. c. p. 1728? 



In Norw. Lithoth. I assumed that L. compactum and L. cir- 

 cumscriptum were to be considered as independent species. After- 

 wards, however, I have found that, strictly speaking, no line can 

 be drawn between them. The same is the case of L. testaceum 

 and L. coalescens. The former of these species is, indeed, de- 

 scribed as bearing sporangia four-parted. But it was only known 



