411 
was undivided as in the normal female trichoblasts, but the following joints had 
produced 4 pericentral cells, and in the 7th joint the formation of sporangia was 
beginning. YAMANOUCHI has formerly described abnormal tetrasporangia in female 
plants of Polysiphonia violacea (1906 p. 425, figs. 168—171). BurrHam found anther- 
idia in tetrasporic plants of Pol. urceolata (1893 p. 298). 
Tetraspores sown in July germinated immediately and gave rise to young plants 
provided with trichoblasts and producing in great part one or two vigorous branches 
at the base (fig. 341). The sporelings obtained by Tobler (1. c.) from carpospores 
showed no trichoblasts. 
P. urceolata has been met with from low-water mark to deep water. The deepest 
observed localities are 31 meters in the North Sea, 26,5 m in the Eastern Kattegat 
and 22,5 m in the Oresund (south of Hveen). It occurs near low-water mark in 
all the waters except the Sound where it has only been met with in 5,7 to 22,5 
meters’ depth, without doubt owing to the varying and often very low salinity of 
the surface water. 
The species is perennial through its creeping filaments. The erect, fructiferous 
filaments are thrown off after the evacuation of the spores, but the sterile ones 
may persist, and the species may be found in every season with erect filaments. 
The length of these varies from 1 to 15 cm and may even reach 23 cm; it does 
not diminish towards the limits of the occurrence of the species. — Antheridia have 
been met with in January to July, procarps in April to June, fully developed cystocarps 
in May but in particular in June to August and further in September (Skagerak), 
and as late as January I have met with cystocarps containing ripe carpospores by 
Frederikshavn. Tetraspores have been met with in May to August and in September 
(Hirshals). The germination takes place immediately, but the new plants seem only 
to fructify in the following year. The species is comparatively often found in a 
sterile state, but there is no general relation between the sterility and the size of 
the individuals. 
The species grows in particular on stones and is very common on moles in 
harbours, but it occurs too on several Algæ, in particular on the stipes of Laminaria 
hyperborea in the Skagerak, further on Phyllophora membranifolia, Furcellaria fasti- 
giata, Fucus etc., on Ascidiae and shells of molluses and barnacles. 
P. urceolata is not very variable. Several specimens from deep localities in 
the inner waters may be referred to f. roseola, remarkable by slender filaments and 
long joints. Small, poorly developed specimens. consisting principally of creeping 
filaments have been described by LYNGBYE as a particular species, Hulchinsia lepa- 
dicola Lyngb. (Polys. lepadicola Ag.) 
Localities. Ns: 6 miles S.E. to E. of Vyl light-ship, 17 m on Lam. hyperb., loose (A. C. Johan- 
sen); aF, off Thyboren, 31 m; Thyboron, on groins; XR, off Orhage. — Sk: Dana 2904 23 m (C. A. J.); YM’, 
Bragerne, 2,5 m; ZK? and ZK}, off Lønstrup, 1 and c. 9m; XO and other places off Hirshals 11—15 m; 
mole at Hirshals; Hojen, within the shoals. — Lf: Krik, pier; Lemvig harbour; XY and LV in Nissum 
Bredning; Oddesund; Thisted harbour; MH, off Skrandrup on firm clay; Nykobing and other places 
