in the Asci of Fungi. 225 



means universally so. Sometimes it is extremely tender and almost 

 gelatinous, so that if a portion of the inner tube with its sporidia be 

 bent at any part by any peculiar position which the sporidia acquire, 

 the outer tube is also forced outwards, and in consequence the asci 

 are sometimes curiously distorted. In some cases they appear toru- 

 lose, from the pressure of the inclosed sporidia, and occasionally 

 when the sporidia assume by accident a transverse position in the 

 tube, I have seen the whole vessel regularly dilated. The apparent 

 thickness of the walls of asci arises in general from the existence at 

 a certain period of growth of a space between the two membranes, 

 and the great difference of thickness at different parts is now easi- 

 ly explained from the greater contraction of those points of the se- 

 condary membrane. This is, I believe, attached to the primary at 

 the apex. In S. pedunculata it certainly is, in which species there 

 is almost always an articulation a little below the point of attach- 

 ment. 



M. Morren's paper is, if I mistake not, calculated to throw light 

 upon the developement of the sporidia themselves. In an early 

 stage of growth the asci contain a meregrumous mass, out of which, 

 probably at the expence of the greater part of the granules of which 

 it is composed as its organization becomes more evident, the sporidia 

 arise. The coat of the sporidia is frequently absorbed before they 

 are discharged, and the asci then contain a number of distinct spo- 

 rules; and sometimes the asci themselves are absorbed, and the whole 

 inner mass of the perithecia consists of sporidia or sporules. These 

 are points to which at present sufficient attention has not been paid, 

 but they would doubtless highly repay the labour of investigation. 



Explanation of Figin-es. 



a. Fractured asci of Sphaeria populina, var. with the secondary 

 membrane projecting. 



b. One more highly magnified, c. A single sporidium still more 

 highly magnified. 



d. Fractured asci of Sphaeria pedunculata, with their sporidia in- 

 volved in mucilage, and partly covered by the secondary membrane. 



e. Portion of one of the asci showing the moniliform arrange- 

 ment, f- Sporidia divested of mucilage. 



g. Asci with one of the paraphyses of a variety of S. peduncula- 

 ta. In one the sporidia are transverse, and the vessel is in conse- 

 quence regularly dilated. 



h. A distorted ascus of Patellaria atrata, with its divided para- 

 physes. k. One of the sporidia. 



