173 



KuTziNG, Caspauy, Thuret (1878, p. 75, pi. 37, fig. 6) and Denys. The outer cortex 

 consists of a greater number of layers of small cells [u]) to 4 or 5) than in Furcel- 

 laria. The longitudinal filaments of the central tissue are mostly thicker at the ends 

 than in the middle "so that they have the form of a femur" (Caspary, p. 94). The 

 cells which form the connection between these filaments and the cortical ones are 

 arranged in regular feebly curved rows running obliquely upwards, while secondary 

 hyphce are wanting ^ Hyaline hairs produced by superficial cortical cells may 

 occur, according to Thuret (1878, p. 75, pi. 37, fig. 6). I have not observed these 

 hairs, but in specimens collected in April I found that some of the peripheral cells 

 were colourless, narrower and longer than the others; probably they were about to 

 develop into such hairs. As to the cell-structure, reference may be made to the 

 paper of Denys. The pit in the transverse wall between the cortical cells is very 

 narrow, while that of the longitudinal filaments is broad, and provided with a 

 double plate. Secondary pits do not occur. The structure of the basal disc has 

 been figured by Kutzing (1843); according to Kolkwitz (1900, p. 51) older discs are 

 stratified. 



The tetrasporangia arise at about the limit between the outer and inner cortex 

 (comp. Caspary, 1850, fig. 21, Thuret, 1878, pi. 36, fig. 6 and 7). As shown by Thuret, 

 an issue is formed outwards to each sporangium by removal of the cells from each 

 other, through which issue the contents of the sporangium is emptied. Specimens 

 with undivided sporangia have been met with in October, with ripe sporangia in 

 January and with emptied sporangia in April. 



The antheridia arise, as shown by Thuret, in nemathecia in particular indi- 

 viduals. According to Guignard (1889, p. 44, pi. 6, fig. 10 — 12) they are placed in 

 tetrads directly on the nemathecial filaments, while Schmitz asserts (1893, p. 8) that 

 they are situated on short cells given off from the filaments. I cannot give any 

 information on this point, as I have not met with male plants in the Danish waters. 



As to the structure and development of the female nemathecia, reference may 

 be made to the classical researches of Thuret and Bornet (1878, p. 77—80, pi. 38—39). 

 These bodies begin to develop in the Danish waters in August or September. In 

 specimens dredged at the entrance to Vejle Fjord, August 20t'i, nemathecia with 

 well developed but unfertilized carpogonia were found. Similar carpogonia but also 

 others with fertilized carpogonia are frequently met with in September. Ripe cy- 

 stocarpia were found in December and January. After the exhaustion of the carpo- 

 spores, the nemathecia are thrown off, while the fronds which have produced them 

 possibly may continue growing. — The germination of the carpospores has been 

 observed by Thuret et Bornet (1878, p. 79, pi. 39, fig. 32); they obtained hemi- 

 spherical bodies producing rhizoids from their under face. 



' Denys speaks (1. c. p. 7) of "Queiiiyphen, welche die Masse der liings verlaufenden durchflechten 

 und seltener auch zwischen die Eleinente der grosszelligen Riiide eindringen". But as he designates 

 the longitudinal filaments also as "Hyphen", it is not clear if it is a case of real hj'phse or only of the 

 above named connecting filaments. As he says, on p. 18, that they occur onlj' "ganz vereinzelt", it 

 seems that he has really observed secondary hyphs, although in very small number. 



