THE GREEN ALGAE OF NORTH AMERICA 373 



1. V. VENTRICOSA J. G. Agardh, 1886, p. 96; Murray, 

 1893, PI. XIII, figs. 6-10 ; Vickers 1908, p. 21, PI. XXIII. A. 

 Frond .solitary, saccate, spherical to pyriform, usually 2-3, rarely 

 5 cm. diam. ; secondary cells formed chiefly at the base for pur- 

 poses of attachment ; membrane smooth, translucent, showing 

 the light green contents. W. I. 



Practically unmistakable for any other species ; Ha/icvstis 

 ova/is, the only one that it resembles, being smaller and an in- 

 habitant of quite different regions. The fronds are usually 

 about the size of a large cherry, but Murray has dredged 

 specimens " as large as a hen's egg." 



2. V. UTRICULARIS Agardh, 1822, p. 431 ; Kutzing, 1856, 

 PI. LXXXVI, fig. 2b-e; Wittr. and Nordst., Alg. Exsicc., 

 No. 953. Cells stout, cylindric-clavate, with similar prolifera- 

 tions ; lower parts of frond decumbent, or creeping among other 

 algae, then erect, up to 5 cm. high, often forming dense tufts ; 

 membrane dark green, shining; zoospores biciliate. Fig. 138. 

 Bermuda, Bahama. /Europe. 



Growing from the literal zone to a depth of 2m.; in the 

 former station the filaments are shorter and stouter ; in the lat- 

 ter longer and more slender. 



3. V. AEGAGROPILA Agardh, 1822, p. 429; Kiitzing, 1856, 

 PI. LXXXVII, fig. i ; P. B.-A., No. 772. Fronds much and 

 irregularly branched, cells subcylindrical, rather short, 2-3 mm. 

 diam., forming a dense, globular tuft; membrane rather dull. 



- W. I. Mediterranean, Indian, Pacific Oceans. 



Nearly allied to V. utricularis, but with more slender, less 

 clavate cells, and forming denser masses, soon freed from the 

 substratum and floating in shallow 'water. 



4 V. VERTICILLATA Kiitzing, 1849, p. 508 ; 1856, p. 30, PI. 

 LXXXVIII; Vickers, 1908, p. 21, PI. XXIII. B; P. B.-A., 

 No. 1533. Cells cylindrical, straight, 2-3 mm. diam., producing 

 whorls of similar cells below the obtuse apex ; branching re- 

 peated, forming tufts about 5 cm. high; membrane very deli- 

 cate and translucent. W.I. 



The regular and frequent whorled branches distinguish .this 

 from all our other species; dried specimens adhere to paper 

 more firmly than in other species. 



s V CONFERVOIDES Harvey, Alg. Ceylon Exsicc., No. 

 7V Wittr. and Nordst., Alg. Exsicc., No. 349. Fronds decum- 

 bent at first, then ascending, cylindrical, 2-3 mm. diam., simple 

 below, above branching sparingly, usually 3-4 branches in a 



