NO. 8 DAWSON : A REVIEW OF THE GENUS RHODYMENIA 147 



Lowest basal parts unknown; fronds composed of branched, terete 

 stipes expanding abruptly into quite regularly dichotomous, flabellate 

 blades, these with the lower segments almost at right angles to the ul- 

 timate stipes; segments 4.5-7 mm. broad, with rounded apices, 150-400 [X 

 thick, composed of many layers of cells showing gradation in size from the 

 small cells of the cortical region to the large ones of the medulla. Tetra- 

 spores and cystocarps unknown. 



Type. — Dredged in 21 fms., west side of bay, shell bottom, Puerto 

 Refugio, Angel de la Guardia Island, Gulf of Calif., Jan. 27, 1940, 

 E. Y. Dawson 252 of Allan Hancock Expedition to the Gulf of Califor- 

 nia, 1940; Herb. Allan Hancock Foundation, AHF no. 3. 



This species from the Gulf is distinguished from R. rhizoides, with 

 which it shows similarities, by the stouter, more extensively terete stipe, 

 thicker blades, and more regular dichotomies of the segments. No stolons 

 are known from the material, since the lower parts of the stipes are 

 absent, possibly because of the raking action of the dredge. 



(42) RHODYMENIA FLABELLIFOLIA (Bory) Mont., Voy. 



Bonite ( 1844-46), p. 105 ; Sphaerococcus flabellifolius Bory, Voy. 



Coquille, Atlas (1826), pi. 17; Howe, Mar. Alg. Peru (1914), 



p. 124, pi. 49; Dendrymenia flabellifolia Skottsb. p.p., Bot. Ergeb. 



schwed. Exped. nach Patagon., IX Rhodophyceae (1923), p. 16 



(ex. illustr.). 



Plate 21, Figs. 24-27 



There has been less confusion surrounding this species than has at- 

 tended Bory's other species, R. corallinaj but presumably only because 

 fewer specimens of sundry collections and localities could be found to 

 resemble his figure. Indeed this species is very unique in the genus and 

 should be confused with no other members. R. flabellifolia has been defi- 

 nitely re-established upon specimens obtained by Coker at Lobos de 

 Tierra, Peru (Howe, lit. cit.). As discussed under R. Skottsbergii, with 

 which it was associated by Skottsberg, R. flabellifolia can readily be recog- 

 nized by the conspicuous, usually stout, much-branched stipe which bears 

 sessile, flabellate blades without any amplexicaul structure. 



Distribution. — West coast of South America; Galapagos Archipelago. 



(43) RHODYMENIA LOBATA sp. nov. 



Plate 19, Figs. 12-13 ; Plate 28, Fig. 41 

 Frons e disco simplici fere non-stolonifera, 20-25 cm. alta, stipiti gracili 

 compressa, 10-15 cm. usque ad laminara primam; segmentis vulgo 3 mm. latis, 

 ultimis 1-2.5 cm. longis, angulis inter segmenta 30° et 40° divergentibus, apicibus 



