84 



III. Siphonales. 



Fam. 1. Codiacew. 



Subfam. Flabellariece, 

 Avrainvillea Decsne. 



1. Avrainvillea nigricans Decsne, 



Decaisne, Sur les Corallines (Ann. Sci. Nat. 2. ser., t. 18, 1842, 

 p. 108). Howe, Phycological Studies III (Bull. Torr. Bot. Club, vol. 34, 1907, 

 p. 491). B0RGESEN, The species of Avrainvilleas hitherto found on the shores 

 of the Danish West Indies (Vidensk. Medd. naturh. Foren., 1908, p. 30). 

 VicKERs, Phycologia Barbadensis, 1908, p. 23, pi. XXX and XXXI (the 

 last named figure sub nomine Avr. longicaulis). A. & E. S. Gepp, The Codia- 

 ce£e of the Siboga Expedition, Monographie LXII, 1911, p. 23, figs. 78 — 80. 



This species is 

 characterized by its 

 very regularly mo- 

 niliform filaments 

 (Fig. 69 a) ; those of 

 the interior are ra- 

 ther thick varying 

 from about bO~10/J., 

 near the surface 

 they grow thinner 

 about 30 /i and get 

 shorter links ; the 

 filaments are here 



woven together 

 forming a rather 

 loose and open cort- 

 ical layer. 



Avi\ nigricans 

 has a rather hetero- 

 geneous habitus. The 

 stipe, which takes 

 its rise from a terete 

 rhizome fixed to the 

 bottom, is terete, though often flattened in the uppermost part, 

 passing evenly into the flabellum ; the stipe can be 10 — 15 cm 

 long and even more, or quite short. The shape of the flabellum 

 also varies much. 



Fig. 69. Avrainvillea mgricans Decsne. 



a and i, parts of filaments; c, chromatophores. 



(a and b, about 70:1, c, 170:1). 



