in the Asci of Fungi. 223 



haps less complete than if the converse were the case. For Mone- 

 ma, a diatomaceous genus, greatly resembles certain asci with their 

 included sporidia ; and I have pointed out in the English Flora the 

 curious analogy between the asci of Sphseria entomorhiza and S. 

 ophioglossoides, and the filaments of Schizonema. 



Be the analogy, however, what it may, between individual Clos- 

 teriae and the asci of Fungi, the point to which I now wish to draw 

 attention is the presence of two distinct membranes in the latter 

 organs, besides the proper integument of each sporidium, viz. the 

 external hyaline tube, and a second, answering to the secondary 

 membrane of Closterise, which at first lines the former closely, but 

 is at length more or less detached. 



The species in which I have seen this most distinctly, are a form 

 of Sphaeria populina, Pers. growing in winter and spring on small 

 fallen branches of ash, and Sphseria pedunculata, Dicks, and Sow. 

 referred in the English Fiora^ on the inspection of dry specimens, 

 as a variety to Sphaeria hypoxylon, but now proved by the detec- 

 tion of recent individuals on the dung of rabbits more or less buried 

 in ant-hills to be a very distinct species, remarkable for several pe- 

 culiarities of structure, which will be adverted to in what follows. 

 The fact, however, being once satisfactorily established in these 

 species, it was clear, from certain anomalous appearances in the con- 

 tents of the asci of various Fungi, that it existed very generally. 

 More especially I have recognized its existence in Sphseria phaeo- 

 comes, Reb. (which I have lately found with perfect asci and sep- 

 tate sporidia) ; an undescribed species detected by Mr D. Stock, 

 on Arenaria peploides ; and Patellaria atrata, Fr. In many other 

 cases I have ascertained the presence of a secondary membrane more 

 or less distinctly ; and I have no doubt that it exists in all asci 

 which are surrounded by a distinct transparent border. 



On submitting to the microscope some of the gelatinous contents 

 of the perithecia of Sph. populina, var. which had been previously 

 moistened, and gently crushed with the point of a lancet, I perceiv- 

 ed that some were snapped asunder, and that from the centre of the 

 fractured part a little hyaline tube projected very much in the same 

 way as is frequently the case in Dentalium entalis. (See Deshayes, 

 Monog. t. 2, f. 2.) This attracted my attention more particularly, 

 and after examining numerous asci I found that it arose from the 

 projection of a fractured portion of a secondary membrane imme- 

 diately enveloping the sporidia, which did not give way so soon as 

 the external tube, which appears to be exceedingly brittle. It is 

 highly transparent, capable of considerable dilatation, but at the 



