F. Borgesen : Rhodophyceæ of the Danish W. Indies. 



101 



Fig. 106. Galaxawa rugosa 

 (Solander) Lamx. Transverse 

 section of the thallus and sur- 

 face cells seen from above. In 

 the cells the campanulate — 

 stellate chro matophores with 

 the pyrenoid in the middle. 

 (About 250:1). 



hand they show just the differences 



Kjellman has noted. 



The most essential and striking 



difference is the smaller development 



of the assimilating filaments. The 



well developed annular groups of 



hairs found in G. sqiialida in the 



younger parts of the thallus were 



not present in these specimens ; only 



in the older part of the thallus hairs 



occasionally occurred. The diameter 



of these hairs was about 16 — 18 /u. 

 The ramification is perhaps 



somewhat more regularly dichoto- 



mous in this species, the internodes 



being nearly of the same length, 



but variations occur. Owing to the lesser development of the 



hairs the surface of the plant is almost quite smooth. The 



annulations are well developed. In the dried 

 specimens the green colour was more promi- 

 nent and the red tinge originating from the 

 hairs in G. sqiialida was lacking. 



As to the anatomical structure I have not 

 found any differences worth mentioning. The 

 fig. 106 shows a transverse section of the peri- 

 feral tissue ; this consists of 3—4 layers of cells 

 the innermost largest; large lobed cells were 

 common, quite in accordance with that which 

 is found in G. squalida. 



In a collection from Lime Tree Bay at St. 

 Croix hyaline unicellular hairs were found abun- 

 dantly in the young tips of the plant (Fig. 107). 

 These hairs grow out from the peripheral cells. 

 They are long, nearly cylindric, when full grown 

 about 200— 300 /i long and 6—8;/ thick. The 

 upper end is filled with protoplasm. Their de- 

 velopment seems to agree perfectly with the 

 description of Rosenvinge as to similar hairs 

 in other Florideæ^). 





Fig. 107. Galaxawa 

 rugosa (Solander) 

 Lamx. Surface cell 

 with long unicel- 

 lular hair. (About 

 175:1). 



1) RosENviNGE, L. KoLDERUP, Remarks on the hyaline 

 unicellular hairs of the Florideæ in BiologiskeArbejder 

 tilegnede Eug. Warming, København, 1911, p. 207. 



