No. -7] REMARKS ON MELOBESIA IN HERBARIUM CROUAN. 5 



nioicles F&lkhg., but even then becoming more and more confluent 

 in an advanced state, here and there leaving holes as in old speci- 

 mens. Occassionally are, on the other hand, to be seen young 

 crusts which are almost reniform. Old crusts are up to aboiit 3 

 cm. in diameter, however depending on the substratum. 



xA section of an old crusts shows a thickness of up to about 

 70 /-t, with up to 8 layers of cells. The basal cells frequently 

 have their longest diameter in horizontal direction, or about 10 p-, 

 and upwards the cells are square or more or less rounded, and 

 rather varying in size, however commonly 8 — 1 1 y. in diameter, now 

 and then also here \\'ith the longest diameter in horizontal direction. 



The conceptacles of sporangia are subconical, about 200 j^- 

 in diameter seen from above, with an apical pore, frequently crow- 

 ded, and sometimes so densely that the roofs become angular. 

 The sporangia are as quoted b}' Crouan four-parted, 45 — 60 /^ 

 long and 30—35 ,0. broad. The conceptacles of cystocarps are 

 smaller than the latter, about 150 jj., and less prominent. 



Some rather young specimens attached to small shells ofsnails, 

 ihe latter about 3 mm. long, I refer to the same species. They 

 are also collected at Plymouih by xMr. Batters, but in another 

 locality than the above mentioned, The}^ differ from t3'pical M. 

 tonale by the crust being more continuous and more regular, with 

 almost entire or slightly lobed margin, now and then furnished 

 with some scattered conceptacles. On a section the crust is shown 

 to be but 20 /j- thick, with 2 layers of cells. However, the cells 

 are here and there undivided, and then almost square, about 18 /^ 

 in diam.eter. Otherwise the basal cells frequently are 4—8 by 

 8 — 14 /A, with the longest diameter in horizontal direction, occasio- 

 nally nearly square, but on the whole rather varying. 



The species is hitherto wiih certainty only known from Brest 

 and Plymouth, but probably also occurring .on the west coast of 

 Ireland according to specimens not yet exactly examined, 



Hapalidium coccineum Crn. , 



Ann. SC. natur. p. 285, t. 21, fig. B. 8-13; Fl. Finist. n. 149. 



= Melobesia zonalis (Crn.) Fosl..? 



