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



6. Interior filaments moniliforui. 2. A. nigricans. 



6. Interior filaments cylindrical, with basal constrictions. 



4. A. longicaulis. 



Page 391, after description of A. LONGICAULIS, add, 



6. A. GEPPII Bbrgesen, 1913, p. 87, figs. 71-72. Frond i2cm. 

 high, rhizome erect, 2 cm. high, i cm. diatn. ; stipe l /3 cm. 

 diain., 5 cm. high, suddenly expanding into a transversely ob- 

 long flabellum, 5.5 cm. high, 8 cm. wide, of rather loose con- 

 sistency, slightly zonate, becoming very thin near the edge ; 

 filaments cylindrical or sometimes here and there subtorulose, 

 30-40 /* diam., diminishing to 14-17 ^ at the surface, apices 

 stouter, subclavate or obtuse, 17-25, rarely 27 n diam ; color of 

 dried specimen gray-green with dull yellow tinge. Dredged 

 in about 16 meters, Virgin Islands, Borgesen. 



Only a single specimen is known. As noted, Collins, 1909, 

 p. 390 and 391, 1912, p. 100, the species of Avrainvillta leave 

 much to be desired, both as to distinction of species and as to 

 nomenclature. 



7. A. ASARIFOLIA Borgesen, 1908, p. 34, fig. 4, PI. Ill; 

 19'3 P- 8 9 fi K s - 73-75; Gepp, 1911, p. 44. Rhizome terete, 

 stipe cylindrical below, flattened above, 6-23 cm, long, 7 mm. 

 diam. ; flabellum oblong-reniform or cordate, to 10 cm. high 

 and 14 cm. wide, entire or lobed, of rather firm consistency and 

 usually distinctly zonate ; surface subglabrous ; filaments of the 

 interior cylindrical or sometimes slightly moniliform, with a 

 rather strong constriction above the dichotomy ; diam. of fila- 

 ments 20-30 n, usually 24-27 ft ; tapering towards the surface 

 and becoming more torulose and more abundantly ramified, ami 

 firmly interwoven; outermost filaments 8-13^1 diam. ; color of 

 dried specimens dark olive green ; substance firm. Dredged in 

 20-30 meters, Virgin Islands, Borgesen. 



Quite close to A. levis, but considered distinct by Borgesen 

 and Gepp. 



Page 392, after description of PBNICILLUS DUMBTOSUS, add, 



Forma KXPANSUS Borgesen, 1913. p. 101. Head larger and 

 looser, its diam. much greater than length of stipe ; stipe 2-4 ctn. 

 long, head 14-17 cm. diam. Dredged in about 30 meters, Virgin 

 Islands, Borgesen. 



Page 393, after description of P. PYRIFORMIS, add, 



Forma KXPLANATUS Borgesen, 1913, p. 99, fig. 81. Filanu-nts 

 of head looser than in the typical form, horizontally expanded 



