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



69 



length of about 250//. They are quite hyahne with the excep- 

 tion of the uppermost end which is almost entirely filled with 

 protoplasm. 



The calcareous layer is 

 rather thick, but uneven 

 and loose ; it extends from 

 the medullary tissue to 

 about the upper third part 

 of the assimilating filaments 

 which are free and protrude 

 freely together with the 

 antheridia and hairs found 

 here. 



The antheridia (Fig. 69) 

 are found on the summit 

 of the assimilative filaments 

 and form dense hemispheri- 

 cal or pyramidal clusters. 

 The development of the 

 antheridia takes place as fol- 

 lows (Fig. 69) : The end of an 

 assimilating filament which 

 is at the same time rich on 

 contents is prolongated coni- 

 cally and divided by trans- 

 verse walls into several 

 small cells ; from these again 



Fig. 69. Liagora elongata Zanard. a, me- 

 dullary cell with assimilating filaments 

 and antheridia. b and c, development of 

 antheridia; d, e, nearly ripe antheridia, 

 e, in transverse section, (a, about 60 : 1, 

 b. c, d, e about 300 : 1). 



small conical outgrowths arise on all sides 

 which soon are divided by transverse walls 

 (Figs. 69 b, c) giving rise to small branches. 

 These are repeatedly di — trichotomously 

 branched into several small branchlets, 

 the end cells of which are the antheridia 

 (Fig. 69 e). 



In the material collected I have only 

 found antheridial plants ; so I cannot give 

 any information as to the carpogonial branch 

 or cystocarp. 



Forms of this species have been fre- 

 quently referred to the Australian plant Liagora Cheyneana 

 Harv., a species which also shows not a little likeness to Liagora 

 elongata. 



Fig. 70. Liagora elon- 

 gata Zanard. Trans- 

 verse section of me- 

 dullary tissue. (About 

 60:1). 



