THE MOULD-FUNGI. 95 



in which small yellow, brown, or black spherules can be 

 distinguished by the naked eye. 



We give a description of the most frequently occurring 

 species. 



Mucor Mucedo (Fig. 20), one of the most beautiful 

 mould-fungi, and one which occurs very generally on the 

 excreta of phytophagous animals, has a transparent white 

 mycelium, which develops numerous and delicate ramifi- 

 cations on the surface of and within the substratum, and 

 which, in its earliest stages of development, and until the 

 sporangia begin to form, is without transverse septa, and 

 therefore unicellular. From the mycelium are thrown up 

 single vigorous branches, the sporangium-carriers ; the 

 points of these branches which, according to Zopf, contain 

 a reddish-yellow fatty colouring matter, swell greatly, and 

 below the swelling a transverse septlim is finally formed, 

 whereby the sporangium is marked off from the sporangium- 

 carrier. The transverse wall becomes arched upwards, and 

 forms a short column termed the columella in the interior 

 of the spherical head, whereby an inner space of peculiar 

 form (1) results. The protoplasm of this space breaks up 

 into a number of small portions, which become surrounded 

 with a membrane and are rounded off; these are the spores. 

 At the same time the sporangium becomes coated on its 

 outer surface with small needle-shaped crystals of calcium 

 oxalate. As soon as the ripe black sporangium takes up 

 moisture, the wall is dissolved, and the spores with their 

 yellowish contents are scattered on all sides along with the 

 swelling contents of the sporangium. The columella, which 

 projected upwards in the sporangium still remains at the 



FIG. 20. 



Mucor Mucedo, after Brefeld and Kny : A, tree-like ramified mycelium 

 with isolated thicker upright branches (a, b, c). 1, Sporangium ; 2. 

 columella and spores ; 3, 4, germinating spores ; 5, 6, development ot 

 the zygospore ; 7, germinating zygospore with sporangium. 



