176 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



Melobesia galapagensis (FosHe) n. comb. 



Farlow 1902, p. 98 (as Melobesia corticiformis) ; Foslie 1907a, p. 9, 

 (as Lithothamnion galapagense) ; 1909, p. 55 (as Epilithon galapagense) ; 

 1929, p. 49 (as L. galapagense) ; Lemoine 1929, p. 59 (as Epilithon 

 galapagense ) . 



Ecuador: Archipielago de Colon, on Pterocladia, Black Beach 

 Anchorage, I. Santa Maria, nos. 34-216, 34-218A and 34-268 (p.p.), 18 

 Jan. 1934. 



Melobesia mediocris (Foslie) Setchell & Mason 



Foslie 1900b, p. 5 (as Lithophyllum zostericolum f. mediocris) ; 

 1907b, p. 26 (as L. mediocre) ; Nichols 1908, p. 347, pi. 3, figs. 1-5 (as 

 Lithothamnion mediocre) ; Foslie & Nichols in Foslie 1909, p. 55 (as 

 Epilithon mediocre) ; Setchell & Mason 1943, p. 45 ; Smith 1944, p. 219, 

 pi. 49, fig. 1. 



Mexico: Baja California, on sea grasses at Pta. Hughes, Cabo San 

 Lazaro, no. 34-661, 7 Mar. 1934. 



Melobesia marginata Setchell & Foslie 



Setchell & Foslie in Foslie 1902, p. 10; Setchell & Foslie in Nichols 

 1909, p. 350 (as Lithothamnion marginatum). 



Mexico: Baja California, on Gelidium, South Bay, I. Cerros, no. 

 34-639 (p.p), 10 Mar. 1934. Ecuador: Archipielago de Colon, on 

 Pterocladia, Pta. Cristofer, I. Isabela, no. 34-198 (p.p), 16 Jan. 1934. 

 Ibid., on Pterocladia, Black Beach Anchorage, I. Santa Maria, nos. 34- 

 216 and 34-268 (p.p.), 18 Jan. 1934. Guayas, on Pterocladia, no. 34- 

 457 (p.p.), 8 Feb. 1934. 



MESOPHYLLUM Lemoine, 1928 



Mesophyllum laxum Lemoine 



Lemoine 1929, p. 60, pi. 2, fig. 3. 



Reported from L San Salvador, Archipielago de Colon. 



LITHOPHYLLUM Philippi, 1837 



Plants forming calcified crusts, plates, or erect, branching forms ; con- 

 ceptacles partly immersed, hemispheric-conical, with an apical pore; the 

 tetrasporangia with a short stalk, arising from the peripheral basal tissue 

 around a central group of short, paraphysislike filaments. 



