— 18 



were fastened downwards to the substratum by means of rhizoids. 



These were shorter or longer without any transverse wall and 



with very thick walls, in this way the lumen of the cell is reduced 



to very little. At the bottom they broaden out to a flat, roundish, 



somewhat lobed disc. 



The erect shoots were sometimes a little ramified, most often 



unbranched. They were ca. 16 — 25/^ broad and the cells 3 — 5 



times as long. They have numerous, 

 small, oblong, short, parietal chroma- 

 tophores and several nuclei (fig. 10 C) 

 especially in the top cell, where often 

 more than ten are present. 



Only tetrasporangia occurred. These 

 were situated terminally on a short 

 one-celled branchlet growing out singly 

 (very rarely two) from the upper end 

 of the mother-cell. Only rarely the 

 branchlet may have two cells; some- 

 times also it has a lateral stalk-cell 

 with a sporangium. The sporangia, 

 being divided tetrahedrally, are ovate- 

 roundish, 46—52^ long and 44—46^ 

 broad; the wall of the sporangia is 

 very thick, 6 — 8^ or more. 



As mentioned above my specimens 

 had only tetrasporangia and this was 

 also the case with all the plants to 

 be found on specimens of Eucidaris 

 Fig. 10. SpermothamnioninvesHens tribuloides collected bv Dr. Th. Mor- 



(Lrouan) Vickers, var. cidaricola ,'. , 



QQY Yar. tens en, who most kmdly placed his 



.4, piece of a plant with creeping and erect material at my dispOSal. 



filaments (25:1). B and C, pieces of erect rxii • • n i i. i n 



filaments with tetraspores {B, 50:1, C, 70: 1). ^hlS SpeCieS WaS foUUd at a depth 



of about 15 fathoms in the sea to the 

 north of St. Jan. It occurred with ripe tetrasporangia in the 

 month of March. 



Gracilaria Blodgetti Harv. 



Harvey, Nereis Bor.-Americana Part II, p. 111. 

 The most characteristic point about this species is as Harvey- 

 has pointed out that "all the branches and their minor divisions 



