NO. 1 TAYLOR : PACIFIC MARINE ALGAE 95 



KEY TO SPECIES 

 1. Plants small, thin and transparent, the dichotomous to irregu- 

 larly branched thallus with strap-shaped segments less than 5 mm 

 wide D. delicatula 



1. Plants larger, the segments foliaceous 2 



2. Main segments of the blade broadly strap shaped, reaching 4.5- 

 5.5 cm in width above the forkings, the thickness to 125 fi, the 

 veins forming just below the branching of the blade . . D. Cokeri 



2. Main segments of the blade deltoid below, but the end segments 

 tapering at the tips; the veins generally forking a second time 

 before the blade divides for the first forking of the midrib ; the 

 thickness to 85 /* D. diaphana 



Dictyopteris delicatula Lamouroux 



Vickers 1908, p. 35, II pi. 3; Setchell & Gardner 1930, p. 149; Tay- 

 lor 1942, p. 62. 



Mexico: Is. Revilla Gigedo, very rare among other algae at Braith- 

 waite Bay, I. Soccoro, no. 34-6, 2 Jan. 1934. 



Dictyopteris Cokeri (Howe) n. comb. 

 Plate 14, Fig. 1 



Howe 1914, p. 70, pi. 13, figs. 5-9, pi. 27 (as Neurocarpus Cokeri). 



The fragments of this plant showing stalk and blades relatively com- 

 plete were within Howe's size limits, but one piece of blade with several 

 forks was itself 45 cm long and 5.5 cm broad at the lower end ; as base 

 and tips were lacking, it must have belonged to a plant exceeding 60 cm 

 in height. The broadest blade was 9 cm across just below a fork. Faint 

 but distinct midribs could be traced in even the largest blades, but lateral 

 veins were definitely absent. 



Ecuador: Archipielago de Colon, dredged from 27 meters' depth 

 off Post Office Bay, I. Santa Maria, no. 34-279, 19 Jan. 1934. Ibid., 

 occasional as dredged from 12-18 meters, «o. 34-353, 27 Jan. 1934. 



Dictyopteris diaphana n. sp.''^^ 

 Plate 15 

 Plants to 4.5-5.0 dm tall, foliaceous, of extreme delicacy, pale brown 

 in color; holdfast about 1 cm broad, cushion shaped, the lower stalk 



■J^O Dictyopteris diaphana n. sp. — Planta ad 5 dm altitudine, foliacea, tenuis- 

 sima, stipitata, stipite ramosa, supra, autem, habente laminam latam et lobatam 

 quae segmentis extremis teretibus praedita; segmentis costas praecociter divisas 

 habentibus; membrana supra crassitudine duarum cellularum, infra, autem, 

 stratum corticeum atque unum vel duo strata medullaria habente. Planta typica in 

 loco dicto Post Office Bay, I. Santa Maria, Ecuador, legit W. R. Taylor no. 34- 

 386 A. 29 Jan. 1934. 



