104 M. FOSLIE. [1905 



in diameter. In young specimens or in feebly developed ones, the 

 conceptacles may be very low and only slightly rising above the 

 surface of the frond. The sporangia are tetrasporic, 50 — 80 fi 

 long and 30 — 50 fi broad. I have sometimes seen bisporic spor- 

 angia which seemed to be fully developed, and which occurred in 

 the same conceptacle as the tetrasporic ones. 



The form limitata is characterized by smoother and appa- 

 rently more solid crusts, which seem to be more incrusted with 

 carbonate of lime than in the typical form. Besides, it is generally 

 more regular in outline than the said form. As to structure, it 

 agrees with the typical form. The conceptacles, on the other hand, 

 are less crowded, often rather scattered, of about the same dia- 

 meter as those of the said form. But they are frequently a little 

 higher and somewhat pointed or subhemispheric- conical and more 

 sharply defined. 



It has been stated by Mr. Rosanoff 1. c. that in M. Lejo- 

 lisii the cells surrounding the orifice of the conceptacles are elon- 

 gated, forming a corona. Concerning M. farinosa is, on the other 

 hand, stated: „L'ostiole est entoure de cellules un peu allongees 

 et un peu relevees, mais qui ne forment jamais une couronne 

 sembable a celle du M. Lejolisii." I have seen conceptacles in 

 M. Lejolisii whose orifices are only subciliate and in all essentials 

 resembling the picture given by Mr. Rosanoff 1. c. pi. I, fig. 8, 

 with the cells 10 — 12 p. long. As to the said picture, Mr. Ro- 

 sanoff, however, declares 1. c. p. 104 that „la couronne de poils 

 n'est pas encore formee." The sporangia, however, seem to have 

 been fully developed so that the conceptacle appears rather to have 

 been on the point of decomposition than not fully developed in 

 any direction. On the oiher hand, there is 1. c. fig. 11a picture 

 of a corona, alleged to be a typical one, the upper part of which 

 is falling to decay. I have examined a great number of specimens 

 of this species, among which several distributed by M. Le Jo lis. 

 But I have not been able to find such a corona as the last men- 

 tioned one. This is perhaps owing to the fact that I have only 

 had dried material for examination, or it ma}' be that the cells of 

 the corona have a short phase of development and are soon falling 



