Ill 



walled, 3 lo 4 times as long as broad, the sporangia 17,5 — 19 /u long, 14 — 15 (16) />« 

 broad. As a contrast to these some specimens may be mentioned which were 

 found growing on Porphyra umbilicalis in Thyboron Channel (Lf); they agreed on 

 the whole fairly well with this form , but the filaments were only 7 — 8 /j. thick. 

 Such a small thickness 1 have otherwise never observed in the specimens referred 

 to this form, though certainly in f. secundata which occurs along the west coast of 

 Jutland; I imagine that these specimens 

 may have originated from f. secundata 

 but have developed in a more sheltered 

 locality. It deserves notice that groin 

 no. 63 is more sheltered than no. 62 

 where f. secundata was found growing, 

 and that the species has otherwise not 

 been found in the Limfjord with the 

 exception of at Hals at the eastern en- 

 trance of the fjord where f. secundata 

 has been met with. — For the rest the 

 specimens referred to this form are on 

 the whole homogenous. 



This form has been found in all 

 the Danish waters within Skagen, from 

 low- water mark to 11,5 meters depth. 

 The specimens found at Bornholm are 

 typical but not very vigorous and with 

 little branched filaments. It was mostly 

 met with in the summer months and is 

 undoubtedly mainly a summer Alga; for 

 the rest it has been met with in the 

 months April to November, in all cases 

 with sporangia. It was most frequently 

 found growing on Polysiphonia violacea 

 and nigrescens , further on Ceramium 

 rubrum a. o. species, Cystoclonium, Zo- 

 stera-]ea.\es, Porphyra umbilicalis and 

 Sertularia pumila. 



Localities. Lf: Thyboran Channel, groin no. 63 , otherwise not found in the Limfjord. — Kn: 

 Harbour of Skagen; Hirsholm; Frederikshavn (Th. Mortensen, !); Nordre Ronner; stony reef by Jegens 

 Odde (GM). — Ks; Lysegrund; D, 11,5 meters. — Sa: Rannen in BegtrupVig; KalaRev; AS, Mejlgrund. — 

 Lb: Fsene. — Sb: KertingeVig. - Sm: Petersvaerft ; Guldborgsand. - Su: BQ, off Ellekilde; Helsingar; 

 Copenhagen. — Bm: QP, Kalkgrund; QR, Gyldenlaves Flak. Bb: Renue; off Allinge. 



/?, tetrica nob. 



Filaments (8 — ) 9 — 12 thick, cells 2 — 4 diameters long, sporangia on opposite 

 branchlets or sessile on the long filaments, all or partly tetrasporous and then 19 — 

 22/1 long, 13—17 /^ broad. 



Chantransia virgatula p, tetrica. A, B and C, young plants 

 seen from above and from the side. D, branched filament 

 with tetrasporangia mosth- on opposite branchlets. E, fila- 

 ment with sessile tetrasporangia. F, two cells showing the 

 chromalophore. 265:1. 



