THE GREEN ALGAE OF NORTH AMERICA 89 



hairs when young, no hairs are found on C. dimorphum. Other 

 details of difference will be found in Svedelius' and Miss Kurd's 

 papers. 



Page 99 of supplement, after note on CODIUM DECORTI- 

 CATUM, add, 



Var. CLAVATUM Collins & Hervey, 1917, p. 56. Densely 

 branched, firmer, less gelatinous ; utricles very variable, mostly 

 clavate, capitate, bell-shaped or turbinate, length 480-980 /*, 

 diam. from 80 \L in- the middle of the smallest utricle to 480 /u. at 

 the summit of the largest. Bermuda. 



A large deep-water form, firm and not collapsing when fresh, 

 but becoming papery when dried. 



Page 99 of supplement, after notes on CODIUM FRAGILE, add, 



10. C. INTERTEXTUM Collins & Hervey, 1917, p. 54; 

 P. B.-A., No. 2018. Frond prostrate, subterete or flattened, 

 closely adherent to the rock, but with tips usually free ; with 

 short irregular branches forming an almost continuous coating. 

 Utricles long, cylindrical or subclavate, 70-90 p. diam., ends 

 truncate or somewhat rounded. Color dark green, substance 

 firm, not specially gelatinous. Forming a continuous belt a few 

 dm. wide on upright or sloping rocks at low water mark. 

 Bermuda, W. I. 



As noted under C. dimorphum, Atlantic records of C. adhaerens 

 on the North American coast should be mostly referred to this 

 species. 



Page 389, and p. 99 of supplement, for Key to the Species of 

 Avrainvillea, substitute, 



I. Upper part a distinct flabellum. 2. 



I. Upper part digitately lobed. i. A. Kawsoni. 



2. Surface of flabellum smooth or smoothish. 3. 



2. Surface of flabellum velutinous, spongy or strigose. 6. 



3. Filaments of flabellum of nearly uniform diam. throughout. 



5. A. Elliottii. 



3. Filaments distinctly tapering. 4- 



4. Filaments 30-40 M diam. below, diminishing towards the surface, 



but ends clavate. 6. A. Geppii. 



4. Filaments smaller, tips not clavate. 5- 



5. Filaments towards the surface torulose, densely matted. 



7. A, asari folia. 

 5. Filaments little or not at all torulose, not so dense near surface. 



3. A. levis. 



