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



Shape of segments very much as in H. Opuntia, but all in 

 one plane. 



Page 403 after description of BRYOPSIS DUCHASSAINGII, add, 



Var. FILICINA Collins & Hervey, 1917, p. 61. Outline of 

 frond broadly or narrowly lanceolate ; main axis not divided; 

 secondary axes closely and uniformly set, often opposite, densely 

 beset from the base with very fine ramuli of equal length. 

 Bermuda. 



The very regularly pinnate branching gives the fronds in this 

 variety an appearance quite different from that of the typical 

 form. 



Page 406, for Key to the Species of Derbesia, substitute, 



I. Filaments 100-600 M diam. . 3. D. Lamourouxii. 



i. Filaments less than 100 M diam. 2. 



2. Sporangia ovoid to subspherical. 2. D. marina. 



2. Sporangia obovoid to broadly pyriform. 3. 



3. Pedicel cell 2-4 diam. long. i. D. vaucheriaeformis. 



3. Pedicel cell i diam. long or less. 4. D.turbinata. 



Page 407, after description of D. LAMOUROUXII, add, 

 4. D. TURBINATA Howe & Hoyt, 1916, p. 107, PI. II, figs. 

 10-16. More or less prostrate : filaments 15-95 fidiam., mostly 

 38-53 /*, sparingly branched, branches subdichotomousor oftener 

 lateral ; lateral branches without septum ; dichotomies with or 

 without i or 2 septa; sporangia broad-pyriform or turbinau-. 

 112-182 /x long, 104-156 wide ; pedicel 14-32 /* long, rarely up to 

 70 /&, 15-21 /idiam. ; pedicel cell cuboidal, 18-21 p, or shorter, 

 10-21 M- Dredged in 28 meters depth on reef 23 miles off Beau- 

 fort, N. C., Lewis Radcliffe. 



Page 427, after account of VAUCHERIA GEMINATA var. K \e>: 

 MOSA, add, 



Var. DEPRESSA Transeau, 1917, p. 228. Fertile branch 

 short, oogonial branches longer than in the type, and depressed, 

 bringing the oogonia to the level of the filament or below. 111., 

 Mich., Transeau. 



Perhaps to be compared with V. uncinatn Kiitz. and V. Wor- 

 on in tana forma ficndula Heering. 



