228 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 12 



Hypnea Marchantae Setchell & Gardner 

 Setchell & Gardner 1924, p. 759, pi. 23, figs. 22, 23, pis. 42a, 56. 

 This material appears to be more delicate than some authentic speci- 

 mens of the species, and to show very few proliferous spines. It does not 

 seem outside the plausible interpretation of H. cervicornis, which is, how- 

 ever, essentially Atlantic-Caribbean in distribution. Material from Ecua- 

 dor was so like Caribbean material that it was, indeed, finally assigned 

 to that species. 



Colombia: Valle, dredged off I. Gorgona, no. 34-493B, 12 Feb. 

 1943. Ecuador: Salinas, dredged at 3.5 meters' depth off La Playa, 

 La Libertad, Schmitt no. 14D-33, 20 Jan. 1933. 



Hypnea cervlcornis J. Agardh 



Taylor 1942, p. 104. 



Ecuador: Guayas, along the shore in pools, Salinas, Schmitt no. 507 

 (tetrasporic), 12-14 Sept. 1926. 



Hypnea spinella (C. Agardh) Kiitzing 



B0rgesen 1915-20, p. 384, fig. 369. 



Mexico: Guerrero, forming mats on rocks, Ba. Petatlan, no. 34- 

 572B. 2 Mar. 1934. 



Plocamiaceae 



Plants bushy, the branches compressed to flat and membranous, fork- 

 ing from the margin alternately to form a flat blade, the lateral branches 

 bearing branchlets in small, usually pectinate groups ; apical cell and axial 

 row evident, the cortex apparently parenchymatous ; tetrasporangia borne 

 on special small branchlets, zonate; carpogenic branch of three cells, 

 borne on a supporting auxiliary cell ; cystocarps scattered along the mar- 

 gins of the thallus or in special branchlets, without evident pores. 



PLOGAMIUM Lamouroux, 1813 

 Plocaniiuni pacificum Kylin 

 Kylin 1925, p. 42. 



These specimens show a great deal of variation in size and habit. 

 Sometimes when very luxuriant the branches are 2.5 mm broad and the 

 branchlets regularly pectinately divided, with the penultimate segments 

 1.0-1.5 mm diam. Sometimes even on the same plant some parts develop 

 a confused and entangled slender branch system with little resemblance 



