96 



der Farbe des Querbruchs unterscheiden, welcher namlich hier (L, 

 polymorphism) nicht triibweiss, sondern schon gelb erscheint". I 

 have not seen fresh specimens of L. incrustans, but judging from 

 L. polymorphum and dried specimens of both, this character is, 

 in my opinion, of less value, as the colour of the surface as well 

 as that of the fracture is also rather varying and often depends 

 on the locality where the plants grow and relations connected with 

 this. However, there can be but little doubt, that the species is, 

 in the sense here taken, identic with that considered by So lms- 

 Laubach to be L. incrustans Phil. He refers to an Adriatic 

 specimen, that he got from Dr. Hauck under the name of L. 

 polymorphum. Also of this form Mad. A. Weber van Bosse 

 kindly sent me two specimens from Hauck's herbarium for exa- 

 mination, which are mentioned below. If not, the name L. de- 

 pressum Crn. has the priority. 



Remark on the form and addition to the description of the 

 species. Of L. depressum Crn. I have seen three authentic but 

 small fragments from the collection in Museum d'Histoire Naturelle, 

 all of which are provided with conceptacles of sporangia, and the 

 one also with those of cystocarps. The crust is about 1 — 2 mm. 

 thick, and the surface is partly nearly even, smooth and somewhat 

 shining, partly irregular, with some few, small and irreguler ex- 

 crescences. The conceptacles of sporangia are irregularly scattered 

 or crowded over the whole frond, seen from the surface strikingly 

 reminding one of small and shallow pin-holes, about 50 — 80 fi in 

 diameter. They at first appear as indistinct depressed-circular 

 points. Later the deepenings get a little larger, the central part 

 deepest, darker and more distinct, the bottom of which forms a 

 part of the roof of the conceptacle. The surrounding part is also 

 slightly depressed and gradually passing into the surface of the 

 frond. I have not seen more than a single canal traversing the 

 centre of the roof, which is to be found also in younger conceptacles, 

 about 15 — 20 \x in diameter. Towards maturity this canal becomes 

 larger, or at length the greater part of the roof falls away, leaving 

 a hole about 80 — 120 p. in diameter, sometimes a little smaller 

 sometimes larger. These holes much resemble passages made by 



