272 



The nodes (genicula) consist of a single layer of very long cylindrical cells 

 with attenuated ends continuing into the joints connected by the node. The state- 

 ment of SoLMs (1. c. p. 28) that these cells are later on divided by a number of 

 thin transversal walls has not been confirmed by Yendo (Genicula, 1904, p. 30), 

 neither have I found these walls. The longitudinal walls of the genicular cells are 

 not incrustated with calcium carbonate, while the attenuated ends (their extrageni- 



cular portions, Yendo) are incrustated as the cells of the 



joints between which they are inserted. For further in- 

 formation on the chemical qualities of the walls of the 

 genicular cells comp. Yendo (1. c). The node is more 

 or less covered by a cortex which is interrupted in the 

 middle (comp. KtiTziNG, Phyc. gen. pi. 79, I). 



Hyaline hairs were not observed in the Danish 

 specimens of this species, but as they have been figured 

 by Thuret in C. mediierranea (Et. phyc. pi. 49 fig. 2 and 4) 

 they will probably also be found in the typical C. officinalis. 



The three kinds of conceptacula occur, as far as 

 known, always on ditferent individuals (comp. Thuret, 

 1. c. p. 93). They are either terminal in the ends of shorter 

 and longer branches, or lateral, sessile on the joints, and 

 the three kinds of conceptacula may all be apical or 

 lateral as well (comp. Solms, 1. c. p. 5). The lateral con- 

 ceptacula are frequently placed on the edges of the joints, 

 but their position may also be more irregular on various 

 sides of the branches. In a male specimen which was 

 very densely beset with conceptacles, many of them were 

 fused together. Two or three of them were frequently 

 placed at the same level, forming an incomplete ring at 



Fig. 196. the upper end of the joint, with the ostioles more or less 



Coraiiina officinalis. Partof frond drawn out in a horizontal slit (fig. 196). 



with fused male conceptacles. 18 : 1. 



As to the structure and development oi the concep- 

 tacles, reference may be made to the repeatedly quoted papers of Thuret and Solms 

 on Coraiiina mediterranean which must be supposed to agree with the typical C. offi- 

 cinalis in this respect. 



As shown by Thuret (1. c. p. 93, pi. 49 fig. 6), the antheridial conceptacles differ 

 from the others in having a conical prolongation containing the ostiole. 1 found 

 the same in the Danish specimens. The development and structure of the spermatia 

 have been studied by Thuret (1. c. p. 95, pi. 49 fig. 7—9), Solms (1. c. p. 36, Taf. II 

 fig. 21-23) and Guignard (1. c). 



The development of the cystocarp has been thorough described by Solms and 

 I must content myself with referring to his paper, remarking however, that the 

 subject needs further examination after the important paper by Minder on Choreo- 



