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



irregular branches to the stipe. 6". elegans has been found in 

 deep water dredging only. 



Page 387, for Key to the species of Codium, substitute, 

 i. Forming a continuous expanded incrustation. 2. 



i. Not forming a continuous incrustation. 3. 



2. Utricles 50-100 M diam., rarely more.- i. C. ditnorphutn. 



2. Utricles 125-200 /* diam., rarely to 300 M- 2. C. differing. 



3. Frond globose to pyriform. 3. C. Ritteri. 



3. Frond branched, cylindric or compressed. 4. 



4. Frond creeping. 5. 



4. Frond erect. 6. 



5. Utricles 150-300 M diam. 4. C. repens. 



5. Utricles 70-90 n diam. 10. C. interte.vtum. 



6. All or part of the utricles tnucrouate. 9. C. fragile. 



6. Utricles blunt, smooth. 7. 



7. Branches usually constricted at base ; utricles 200-300 M diam. 



6. C. isthmocladnm. 

 7. Branches not usually constricted at base. 8. 



8. Frond normally cylindric throughout ; utricles seldom reaching 

 200 M diam. 5. C. tomenlosum. 



8. Frond normally more or less compressed. 9. 



9. Utricles seldom less than 300 M diam. ; compression chiefly at axils. 



7. C. dfcorticatum. 



9. Utricles usually less than 250 M diam. ; often compressed throughout. 



8. C. Lindenbergii. 



Cancel paragraph beginning " i. C. ADHAKRENS" and fol- 

 lowing paragraph, and substitute, 



i. C. DIMORI-HUM Svedelius, 1900, p. 300, PI. XVII, figs. 

 16-19; A. M. Kurd, 1916, p. 211, PI. XXXVII; C. adhaerens 

 P. B.-A., No. 523, not of Agardh. Frond prostrate, dark green, 

 about 5 mm. thick, margin irregularly lobed ; interior of slender 

 filaments, exterior of utricles 50100/1 diam., commonly 75 /*, 

 the end wall sometimes thin, sometimes much thickened, show 

 ing distinct stratification. No hairs present. Pacific coast from 

 Alaska to San Diego. Patagonia. 



It is unlikely that true C. adhaerens occurs in North America. 

 All specimens from the Pacific coast as far as examined prove to 

 be C. dimorphum, all from the Atlantic coast C. diffornte or 

 C. intcrtextum. In C. dimorphum the differentiation of the 

 utricles as to the character of the end wall is quite marked, the 

 two forms usually occurring on the same individual, and in 

 different parts of the frond. C. adhaerens produces abundant 



