82 TUFTS COLLEGE STUDIES, VOL. IV, No. 7 



branched near the surface of the water. Point Lobos, Cal., 

 N. L. Gardner. 



A form of deep quiet pools, little affected by the tide : very 

 different in appearance from the loose matted typical form, but 

 without technical characters sufficient for specific separation. 



Page 356, after SPONGOPSIS SACCATA, add, 



54. C. UNCINATA Borgesen, 1913, p. 20, figs. 9 and 10. 

 Densely tufted, 4-5 cm. high ; attached by branching rhizoids ; 

 main filaments no p. diam., cells 10-15 diam. long, with thick 

 wall and frequent annular constrictions; branches 65 n diam., 

 without constrictions, cells 4-6 diam. long, di-trichotomously 

 branched, with scattered or secund ramuli, 35 p diam., often 

 hooked or circinate ; color dark green. Virgin Islands. 



Amply distinct by constricted axes and' strongly hooked 

 ramuli. 



55. C. CORALLICOLA Borgesen, 1913, p. 21, figs. 11-12; 

 P. B.-A., No. 2010. Densely tufted, decumbent filaments at- 

 taching to the substratum and emitting erect branches ; main fila- 

 ments 125-150 n diam., cells 5-10 diam. long, cells in secondary- 

 branches and ramuli 70 ft diam., 5-6 diam. long. Branching 

 di-trichotomous below, few branches above, branches more or 

 less curved or sinuous ; cells more or less clavate ; rhizoids 

 abundant, 45 M diam. Bermuda, Virgin Islands. 



56. C. PISCINAE Collins & Hervey, 1917, p. 46; P. B.-A., 

 No. 2165. Main filaments roo/tdiam.; ultimate ramuli 50 /* ; 

 cells 3-5 diam. long, nodes not constricted ; terminal cell rounded 

 or truncate ; branching by wide, equal, distant forkings, with 

 distant, patent ramuli above ; color light green ; substance 

 somewhat crisp but not fragile. Bermuda. 



In still water of a fish pool, forming large, loose masses, in 

 appearance like some of the larger species of Spirogyra. 



57. C. RIGIDULA Collins & Hervey, 1917, p. 47. Main fila- 

 ments 120 /* diam., secondary 100 /*. ultimate cells 80 ft ; cells 

 1-2 diam. long, nodes not constricted ; terminal cell usually 

 longer, sometimes 3 diam., rounded or subacute ; branching at 

 base by broad forkings, at first frequent, then distant ; branches 

 in upper half of frond long, straight, with ramuli nearly or 

 quite at right angles, distant and scattered below, near the tips 

 in secund series ; color rather dull light green ; substance firm 

 and harsh. Bermuda. 



Iti some respects like the preceding species, but coarser and 



