72 "VAN TIEGHEM AND LE MONNIER. 



rangioles of Thamnidium. By pressure the thin granular, 

 brittle, and greyish membrane of the sporangiole is easily 

 broken, and the smooth, often dark slate-coloured spore is 

 extruded (fig. 23, b). But germination affords the most con- 

 vincing proof of the sporangial nature of the reproductive 

 body. 



A fruiting branch of Chcetocladium Jonesii, terminating in 

 a point, and bearing upon its middle dilatation eight ripe 

 reproductive bodies, still attached to their pedicels, is placed 

 in a drop of orange-j uice in a cell. Seven hours afterwards 

 the external membrane is ruptured, and the contained spore 

 either completely (fig. 23, cc) or partially (c?) extruded, re- 

 quiring in the latter case a little manipulation to detach it 

 from the sporangiferous branch. The spores now change 

 colour, and gradually swell to three or four times their 

 original diameter without, however, changing form ; a 

 large vacuole occupies its centre (fig. 24, a). They then 

 become oval, and afterwards form projecting angles {h, c, d), 

 which develope into short stout tubes, spreading in all 

 directions and dividing immediately into close or palmate 

 dichotomies (fig. 24, e to fig. 27), and forming a small mass 

 of mycelium, which grows slowly by additions to its peri- 

 phery, attaining sometimes the size of a pin's head. No long 

 diffuse branching mycelium with radicles is formed, as in 

 Mucor, where the mode of germination is altogether differ- 

 ent. This enables us to detect as early as the second day 

 an accidental admixture in our cell-culture oi Mucor spores. 



It is not till three or sometimes four days from the time 

 of sowing the spores that branches of these white mycelial 

 masses erect themselves into the air to ramify in all direc- 

 tions. These long aerial hyphae bear laterally either singly 

 or in verticils of two or three branches, which terminate in 

 a point, and which bear in turn at about their middle two 

 or three shorter pointed branches. These last bear on a 

 swelling at their middle, a small number of slender simple, or 

 sometimes dichotomous pedicles, each terminated by a mono- 

 sporic dark slate-coloured granular sporange, and measuring 

 •006 to *008 mm. in diameter (fig. 22). As the fructification 

 develops, the protoplasm, slowly accumulated at first in the 

 large radiating mycelial hyphse is used up, and the hyphae 

 become empty. At the same time the extremities of some of 

 them abruptly taper off, while others become enormously 

 inflated into large balloon-like bodies, with a granular sur- 

 face, and often prolonged into a point (fig. 28, a, h). But we 

 have never detected chlamydospores. 



This is the uniform course of development in Chcetocladium 



