JOURNAL OF MICROSCOPICAL SCIENCE. 
EXPLANATION OF PLATES XVII & XVIII, 
Illustrating Prof. M‘Nab’s paper on the Life-History of 
Penicillium. 
Figs. 
1.—Young sclerotium in transverse section. a. Carpogonium-hyphe sur- 
rounded by sterile tissue; 4, the cells of the sterile tissue, 
smallest near the carpogonium-hyphe ; c, mycelial hyphe. x 300 
diameters. 
2.—Sexual organs after fertilisation. a. Fertilized carpogonium; 3, 
sterile hyphz, which appear near carpogonium after fertilization. 
x 630 diameters. 
3.—The same in a more advanced stage. The enlarged carpogonium in 
a nearly surrounded by the sterile hyphe 5. x 630 diameters. 
4.—Sclerotia of Penicillium. «@. Simple sclerotia showing extremes in 
size; 6, coherent sclerotia. Xx 15 diameters. 
5.—Section of sclerotium of Penicillium after cultivation for eight weeks. 
a, Marginal zone; 4, sterile (nutrient) tissue; ¢, carpogonium- 
hypha with transverse septa; d, portion of another carpogonium- 
hypha with the cells producing branches of two kinds, the thicker 
afterwards forming the asci, the thinner the nutrient mycelium ; 
e, carpogonium-hyphz showing both thick and thin branches 
arising from the same cell; /, carpogonium-hypha cut across ; 
g, empty space out of which the carpogonium-hyphex have dropped ; 
A, carpogonium-hypha surrounded by a rosette of cells. x 300 
diameters. 
6.—Developing carpogonium-hyphe. 1. Septate carpogonium-hypha ; 
2, ascus-producing branch with its curved apex; 3, much- 
branched mycelial (nutrient) hypha. x 630 diameters. 
7.—Section of sclerotium of Penicillium after cultivation for from 5—6 
months. a. Yellow marginal zone; 4, sterile tissue; c, mycelial 
hyphe ; d, hyphee bearing asci; e e, crystals of calcium oxalate ; 
J; vipe spore. xX 300 diameters. 
8.—End of hypha bearing an ascus with nearly ripe ascospore. x 630 
diameters. 
9.—Ascus-bearing hyphe, some of the asci ripe. X 630 diameters. 
10.—Axial hypha with all the asci detached from their stalk-like bases. 
x 630 diameters. 
11.—Ascospores of Penicillium. a. upper view; 4, side view. x 800 
diameters. 
12.—Germination of ascospores in fruit juice ; a, by splitting of exosporium 
into halves; 4, by one-sided opening. x 800 diameters. 
