159 



in the middle of tlie tricliogyne two bodies were found which were probably nuclei. 

 As no spermalia were found fixed to the Irichogyne, the two nuclei must have 

 derived by division from the original carpogonial nucleus, the undermost represen- 

 ting probably the sexual nucleus, the upper the trichogynal nucleus. It must 

 however be admitted that the upper end of the tricliogyne was not quite distinctly 

 visible. This filament is further remarkable in that the second cell from the base 

 acts as an auxiliary cell, having fused with a sporogenous filament from another 

 carpogonium. It is however not fully clear if the great fusion cell has arisen from 

 the second cell or by division from the first cell, which is rather small and half 

 enclosed by it. In the first case the carpogonial filament has been 6-celled. 



The species is widely distributed on the Danish coasts, and occurs often abund- 

 antly. It grows particularly in somewhat sheltered localities, and attains there the 

 greatest dimensions. In Sk, Lf, K, Sa, Lb and Sf it has been found only at low- 

 water mark or a little lower; on the other hand, in the southern and eastern waters 

 (southern parts of the Great Belt and of the Sound and the Baltic) it has also been 

 met with in depths of 4 to 12 meters, and it occurs in a similar manner in the 

 western Baltic according to Reinke (1. c), while it otherwise appears to grow only 

 at a slight depth. On the shores of North Europe it grows, where tide occurs, in 

 the middlemost part of the littoral region ("a mi-maree"). The explanation of this 

 peculiar distribution in the western Baltic and the adjacent waters might perhaps 

 be sought in the lesser salinity of these waters. It deserves to be mentioned in 

 this connection that the species, according to Crouan (F1. Finist. p. 144), in the 

 neighbourhood of Brest occurs particularly where fresh water runs out. When 

 growing at low-water mark in Danish waters of comparatively high salinity, the 

 plants are also temporarily exposed to fresh water at least by rainy weather during 

 low-water. On the other hand it will be seen from the following maximal lengths 

 for specimens collected in a series of localities in the Sound ranged from North to 

 South that the length decreases with much decreasing salinity: Hellebtek 47 cm, 

 Humlebifik '^Ocm, Sletten 28 cm, Trekroner (Copenhagen) 20 cm, Dragor 8 cm. These 

 specimens were all collected near the low-water mark. A length of over 50 cm 

 has been met with in specimens from Lb, Sf (70 cm) and Sb. In the other waters 

 the following maximal lengths have been recorded: 8k 37, Lf 28, K over 30, Sa 40, 

 Su 47 cm. 



The species has been found with erect fronds at all seasons, but only abund- 

 antly in the first half of the year, from the middle or the end of the winter to the 

 beginning of the summer. Most of the specimens die in June or July; only single, 

 rare specimens are therefore met with in the more advanced summer and in autumn. 

 As the spores germinate easily immediately after having been shed, the species 

 must be supposed to endure the summer in a crustaceous form, originating for the 

 most part from the spores shed in the last spring but partly also of older date. 

 The sexual organs have been met with in winter and spring and in September, ripe 

 cystocarps in May to July, ripe tetrasporangia in May to July, once even in August 



