118 L. HILLIS-COLINVAUX 



Nodal medullary filaments uniting in pairs for a distance of 1-1-5 times 

 the filament diameter, also fusing for a short distance in threes, rarely fours, 

 and sometimes remaining single ; the fusion units commonly adhering firmly 

 in one or a few groups. 



Type specimen. Philippines, Sta. Ana, Pro v. Cayagan, Luzon 

 Island, Velasquez 2379, 17 July, 1950 (MICH); isotype material at 

 the University of the Philippines. 



Habitat. From about — 3 m to — 100 m. The shallow records are 

 from rock tidepools and surge channels in Guam, both with strong 

 currents (R. Tsuda, personal communication) ; the deep records 

 were obtained by dredging during the Sealark Expedition, 1905, 

 with specimens housed in the British Museum (Natural History). 



Geographic distribution. Western Indian Ocean ; western Pacific, 

 both north and south. 



Halimeda copiosa Goreau and Graham 



Figures 33, 101. 



Halimeda copiosa Goreau and Graham (1967), p. 433, Figs 1-10. 

 Halimeda liederacea L. H. Colinvaux (1968a), p. 30, Figs 1-3, 6; (1969a), p. 88. 

 Halimeda opuntia f. hederacea Barton (1901), p. 21, Plate 3. 

 Halimeda opuntia v. hederacea (Barton) Hillis p.p. (1959), p. 360. 



Plants to 70 cm long, loose or compact of habit, from a single holdfast; 

 calcification moderate; branching in a single plane, most commonly 

 dichotomous but also trichotomous ; segments commonly one to three ribbed 

 although not strongly so, a "skin" of peripheral utricles sometimes separating 

 from the rest of the cortex when the segment dries ; the first two or three 

 segments at the base of the thallus and often the first on a branch small, 

 trilobed, terete or rhombic, other segments transversely oblong to depressed 

 ovate with upper margin entire, three-lobed or crenate, and basal margin 

 truncate to cordate, often forming a short stalk at the nodal junction, to 

 13 mm long, 21 mm broad, and 0-3-l*0 mm thick when dried. 



Cortex of three to four series of utricles with subperipheral ones usually 

 not utriculiform ; outermost utricles adhering firmly for about 1-5 yun.; in 

 surface view polygonal with polygons measuring (22-)28-46(-64) [xm in 

 diameter or if only the utricles with hexagonal surface appearance considered 

 then (27-)32-46(-64) [j,m; in section outermost utricles (22-)30-50(-68) [xm 

 long, not more than four supported by each secondary utricle; secondary 

 utricles (16-)19-30(-45) [im broad. 



Medullary filaments numerous in mature segments, most commonly 

 united at the node in pairs, less commonly in threes to sixes, all for a short 

 distance; occasionally fused in pairs for about two to three times this 



