NO. 1 TAYLOR : PACIFIC MARINE ALGAE 205 



HALYMENIA C. Agardh, 1817 



Plants of moderate to considerable size, foliaceous or bushy, generally 

 of quite softly fleshy consistency; when branched, variously lobed or 

 dichotomously or pinnately divided ; structurally showing in the medulla 

 slender filaments well separated in a soft jelly, often radiating from con- 

 spicuous ganglia, the cortex of large cells within, small cells without, not 

 in evident filamentous arrangement ; sporangia tetrapartite, scattered and 

 immersed in the cortex; cystocarps immersed, with a pericarp of slender 

 filaments, discharging through a definite pore. 



KEY TO SPECIES 



1. The plant freely dichotomously branched, the branches subterete 

 H. Agardhii 



1. Branches flat to foliaceous 2 



2. Arachnoid medullary ganglionic cells not conspicuous . . 3 



2. Arachnoid cells in the medulla prominent . . . H. actinophysa 



3. Outer cortical cells to 9 ju, diam. ; plants to 30 cm tall, the lance- 

 olate segments to 4 cm wide H. santamariae 



3. Outer cortical cells 15-25 /x diam. ; plants to 12 cm tall, narrowly 

 ligulate, the segments to 1.5 cm broad H. utriana 



Halymenia Agardhii De Toni 



Weber-van Bosse 1921, p. 237; Taylor 1928, p. 199, pi. 26, fig. 18, 

 pi. 28, fig. 8. 



Mexico: Nayarit, dredged from 22 meters' depth at sta. 970 near 

 I. Maria Magdalena, Las Tres Marias, no. 39-646A, 9 May 1939. 



Halymenia santamariae n. sp.^^i 

 Plate 64, Fig. 1 



Plant to 30 cm tall, foliaceous, divided into lanceolate segments 4 cm 

 broad, or these lobed toward the apex, rose colored, gelatinous, thin, about 

 75 II thick when soaked up ; the medulla sparse, of slender filaments near 



121 Halymenia santamariae n. sp. — Planta ad 3 dm altitudine, foliacea, gela- 

 tinosa, in segmentis lanceolatis 4 cm latitudine, ad cacumina lobatis, circa 75 y. 

 crassitudine divisa; medulla sparsa, constante e filamentis parietem tenuem habenti- 

 bus et refractivis, ganglia interdum formantibus; cortice constante e strata inte- 

 riore imperfecto, et strato exteriore cellularum 6-9 |x diam., eadem fere crassitudine 

 gelatinae separatarum; tetrasporangiis dispersis, 9 \i diam., ad 15 \i long. Planta 

 typica in loco dicto Post Office Bay, I. Santa Maria, Ecuador, legit W, R. Taylor 

 no. 34-383. 29 Jan. 1934. 



