242 



usually no such formation was to be seen. The sporangia are, when fully devel- 

 oped, four-parted, 45—77 // long, 32 — 49 u. broad. While at first vertically placed, 

 they may sometimes finally become horizontal, at all events when the conceptacle 

 contains only one or two developed sporangia (fig. 158 D — E). 



The antheridial conceptacles are small, often very small, and but little pro- 

 minent if at all. As shown by Mrs. Weber-van Bosse (1. c), the spermatia are 

 produced at the end of long sterigmata developed from a layer of very small cells 

 covering the basal layer (fig. 159 A, C). In some cases, however, the cells producing 



the sterigmata are 

 not placed di- 

 rectly on the ba- 

 sal layer (fig. 158 

 JS, C). In some 

 cases the concep- 

 tacle was found 

 provided with a 

 long slightly cur- 

 ved spout agree- 

 ing exactly with 

 that described by 

 Mrs. Weber (fig. 

 158 C); but in 

 most cases no 



Mclobesia Lcjolisii. A and Ji from Holba k Fjord, A, antheridial conceptacle. B, female SUCh SpOUt WaS 

 concentacle, sliowing carpotjonia. C, antlieridial concepUicle. D, cystocarpic conceptacle, be SCeU. The 



C (550:1, tlie rest 350 : I . 



ostiole was then 



a simple small hole without any peristome. The spermatia appeared sometimes as 

 slightly elongated cells with pointed ends (fig. 159 C). 



Well developed female conceptacles were only rarely found. The conceptacles 

 shown in figs. 157 B and 159 B are certainly female ones, containing unfertilized 

 carpogonia, and fig. 159 D represents a cystocarpic conceptacle with the carpospores 

 placed at the periphery only. A disc-cell could not be distinguished. Peristomial 

 hairs seem not to be developed. The diameter of female conceptacles was found 

 to be 123—175//. 



Ripe tetrasporangia have been found in summer (June to September), anthe- 

 ridia in May and September, and cystocarps (with few spores) in May. 



I have referred to this species all the specimens growing on old Zosfera-leaves 

 and referred by Foslie to M. LejoUsii f. typica, with the exception of one sample 

 mentioned below under M. subplana. The species has also been found growing on 

 Ruppia. The specimens growing on Algae, on the other hand, seem to belong to 

 other species, which are mentioned below. The species has been found in depths 

 of 1 — 11 meters. 



