92 



Crouan's collection in Museum d'Histoire Naturelle. One of these 

 is provided with newly emptied conceptacles of sporangia coinci- 

 ding with those of the species in question, and Crouan quotes 

 the sporangia to be tetrasporic, and it in all accords well with 

 L. polymorphum. It is only about 1.5 mm. thick, but overgrown 

 conceptacles are visible from the side of the fragment. The roofs 

 of the emptied conceptacles are fully dissolved, but not any part 

 of the border, the holes 150 — 180 p. in diameter, and including 

 the border the conceptacles have been 200 — 300 p. in diameter 

 seen from the surface. Two of the other fragments destitute of 

 conceptacles perhaps or probably also are referrible to the same 

 species. The fourth on the other hand seems to be somewhat 

 differing, but it is too small and fragmentary to be determined, as 

 it only forms a part of the peripherical portion of af larger specimen. 



Relation to other species. As remarked under L. varians 

 these two species may easily be confounded in a sterile stage. 

 So also in regard to the following species, L. incrustans. They, 

 are, however, distinguished by characters quoted under the latter. 

 The species on the other hand sometimes approaches in habit cer- 

 tain forms of L. papillosum Zanard. 



A specimen that 1 got from Dr. Bornet, gathered at „Le 

 Croisic (Loire Inferieure)", rather resembles in habit L. papillosum 

 Zanard. in Hauck, Meeresalg. t. 2, fig. 4, with smaller or larger 

 processes. I, however, found some few conceptacles of spo- 

 rangia, which fully accord with those in L. polymorphum, and,, 

 no doubt, being a form of this species most nearly related to f. 

 papillata. Overgrown conceptacles are numerous, but I have not 

 seen the sporangia. 



A British specimen gathered at Swanage by Mr. Batters is 

 nearly related to the latter in habit, however, with more numerous,, 

 a little larger and more irregular knobs. It not unlikely is also a 

 form of L. polymorphum, but it is sterile and, therefore, the deter- 

 mination not certain. 



Of L. papillosum Mad. A. Weber van Bosse kindly sent me 

 3 specimens from Hauck's herbarium for examination. Two of 

 these fully coincide with Hauck's description 1. c, and it probably 



