134 



L. HILLIS-COLINVATJX 



In comparing it with discoidea, the surface utricles of discoidea are 

 smaller (average diameter 65 [xm), and the secondary utricles larger 

 (average 125 [xm as compared to 90 [im in gigas). 



Halimeda macrophysa Askenasy 



Figures 40, 99. 



Halimeda macrophysa Askenasy (1888), p. 14, Plate 4, Figs 1-4; Barton 

 (1901), p. 17, Plate 2, Figs 15-18; Hillis (1959), p. 351, Plates 2, 5, 6, 11. 



Fig. 40a. H. macrophysa. Habit. Scale bar is 2 cm. (Photograph by The Ohio State 

 University Department of Photography.) 



Plants fragile, compact and erect, arising from a single small holdfast 

 region, to 10 em tall; calcification moderate; the surface dull, rugose and 

 appearing pitted; branching complanate, mainly ditrichotomous but with 

 several segments arising from some of the larger ones ; ba sal segments often 

 subcuneate, the others friable, plane, commonly reniform or subreniform but 

 also subcuneate, the upper margin entire, to 15 mm long, 24 mm broad and 

 averaging 0-5 mm in thickness. 



Cortex most commonly of two layers of utricles; outermost utricles 

 separating readily on decalcification, appearing round in surface view, 

 135-180 [Jim in surface diameter, 170-230(-290) (xm long, most commonly 

 two but also one or four supported by each secondary utricle; secondary 

 utricles 40-100 {zm broad, 73-140(-230) [im long. 



