SPORODINIA. 143 



gently in water : examine under a low power, and 

 observe 



1. The branched hyphae, which are light-coloured, 

 and rarely septate when young, but assume a brown 

 colour, and form numerous transverse septa at irregular 

 intervals as they grow old. 



2. The large brown zygospores, each supported by 

 two thicker, club-shaped hyphse (Syzygites form). 



3. The relatively small sporangia borne on branched 

 gonidiophores, and having a structure similar to those 

 of Mucor (Sporodinia form). 



Compare a number of zygospores in various stages 

 of development, and observe in them the following 

 points 



1. The swelling of two neighbouring mycelial fila- 

 ments (suspensors), and their assumption of a position 

 with their two swollen ends opposite one another. 



2. The formation of transverse septa cutting off the 

 apical part of each suspensor, thus forming the two 

 gametes. 



3. The two gametes in close contact with one 

 another, while the walls at the point of contact are 

 gradually absorbed, the absorption beginning at the 

 central point : the two protoplasmic bodies thus coalesce 

 to form the zygote or zygospore. 



4. The increase in size of the zygospore, its contents 

 becoming dense and oily, while the wall at the period 

 of maturity consists of the following successive 

 layers 



a. The primary membrane of the gametes, which 

 remains thin, but persistent as an external covering. 

 I. The epispore, which is a dark-coloured firm or 



