194 American Quarterly Microscopical Journal. 



is sometimes quite so. This division wall can be best seen in 

 the sporangium just before it opens to give exit to the spores. 



E. — Foreign bodies. 



In specimens of pedunculosum, taken from a flower-pot. were 

 many eggs of Anguilliila in all stages of development. They 

 lay in the tissue of the leaf stem, between the cells. The ani- 

 mal was often found on sections of the stem, but never in the 

 tissue. It was probably displaced by the cutting of the sec- 

 tions. The earth in this pot contained many specimens of the 

 same animal, but from the absence of sexual forms, no deter- 

 mination of the species could be made. No animal parasites 

 were found in the leaves of this plant, but the epidermis was 

 permeated with mycelial threads, and presented numerous 

 swellings, filled with fluid. Notwithstanding both parasites, 

 the plant was in an apparently vigorous condition. 



A FEW REMARKS OX ANGULAR APERTURE, 



AND DESCRIPTION OF A -UNIVERSAL 



APERTOMETER." 



BV PROF. H. L. SMITH. 



{Received February 24th, i8jg.) 



In venturing a few remarks upon the vexed question of 

 angular aperture, and those scarcely orthodox as the subject 

 is viewed by many, and for which I may receive the same 

 kind of treatment that Mr. Wenham has experienced, I am 

 not actuated by any desire to appear as the champion of a 

 " lost cause," as some have called it, but I desire to make a 

 few statements, the truth of which any one may readily test, 

 and which I am confident few, if any, will deny. 



Recently I invited a well-known optician to determine for 

 me the angular aperture of what, to all appearances, was a 

 Powell & Leland i-iath inch, of old date. He readily con- 

 sented, and after measuring it precisely as he would have 

 done one of his own objectives, the same way in which he 

 could obtain 179' for some of them, he announced the result, 

 89'. This, indeed, did not seem much for a i-i2th, even if 

 it was made in 1852. I then told him that I had previously 

 removed both back svstems. and that he had been measuring 



