JOURNAL OF MICROSCOPICAL SCIENCE. 



DESCRIPTION OF PLATE XI, 

 lUustrating Dr. Lindsay's paper on Lecidea lugubris, Sommf."^ 



Pig. 



1.— Fragment of the lichen, slightly magnified. ; 



a. Apothecia iu different stages of development. 



b. Spermogones scattered over the squamules. 

 2.'~-i'ragmeut of the thalline squamules, magnified, showing the — 



a. Apothecia. 



b. Spermogones. 



3.— Sterile squamules, magnified, showing spermogones. 



a. Papillate ostiole. 



b. Depressed ostiole. 

 4.-*~Section of two spermogones — 



a. Having a papillate ostiole ; and 



b. A depressed ostiole. 



5. — Section of apothecium, magnified. 



a. Exciple or margin. 



b. Hymenium or thalamium. 



6. — Section of apothecium and spermogones, showing their relative position, 



a. Apothecium. 



b. Mature; and 



c. Young, undeveloped spermogones. 

 7. — Section of apothecium, showing— 



a. Knobbed extremities of paraphyses. 



b. Filaments of ditto. 



c. Hypothecium. 



d. Mature theca : its body. 



e. Ditto, its pedicle. 



/. Ditto, ruptured, showing the mode of escape of the 



spores. 



* The observations, upon which the drawings are based, were made chiefly 

 under power 380 of a Nachet's microscope. 



