80 M. FOSLIE. [1905 



said species, only less smooth. It bears, however, four-parted 

 sporangia and is, therefore, to be referred to Ph. polymorphum. 

 Be it said that the alga never attains to the thickness of Ph. 

 polymorphum, and the conceptacles are not to be found overgrown 

 by new formed tissue. 



As to structure the species in all essentials corresponds with 

 Ph. polymorphum, though the hypothallium is generally more 

 faintly developed than in the latter. 



Also the reproductive organs are like those of the said spe- 

 cies. In some places the conceptacles frequently bear peculiar local 

 formations of tissue forming a disc-shaped layer over the roof 

 (L. emboloides Hey dr.). These formations, however, rather soon 

 fall into decay and are sometimes found also in several other 

 species. 1 ) The two-parted sporangia are 120 — 150 {J. long and 

 40—60 fi broad. 



The species in question occurs on rocks, stones and shells of 

 molluscs in the lower part of the litoral region and in the upper 

 part of the sublitoral region, in the former one sometimes asso- 

 ciated or even anastomosed with Lithoth. Lenormandi. Some- 

 times it also seems to occur attached to other calcareous alga?. 

 The species descends to a depth of about 10 fathoms, and occurs 

 in about the same conditions as Ph. polymorphum. It seems, 

 however, to prefer more sheltered localities than the said species, 

 having not yet been found in shallow water at the open coast. 

 As far as is hitherto known, the alga is most frequent on the 

 coasts of Denmark, where like Ph. polymorphum it has been 

 found in many places. It seems also to be of common occurrence 

 at Helgoland associated with the said species. Although it is 

 rather widely dispersed, it is on the other hand known only in 

 small numbers from the other areas recorded below. The alga 

 develops reproductive organs at any season of the year ; but sterile 

 specimens are often met with analogously to the state of things in 

 the case of the species preceding. 



1 ) Cp. M. F o s 1 i e. Bieten die Heydrichschen Melobesien-Arbeiten eine sichere 

 Gmndlage? — Det Kgl. norske Videnskabers Selskabs Skrifter 1901. No. 2. 

 Trondhjem 1901. Pag. 11. 



