2238 Journal of Applied Microscopy 



10. Crush a ripe antheridium under the cover-glass and draw one of the 

 numerous filaments inside. The small cells of these filaments contain the sper- 

 matozoids. Draw a single cell showing a mature spermatozoid. How many 

 cells in a single filament ? Suppose the antheridium contains 8 x G x4 filaments, 

 how many spermatozoids would there be produced in each antheridium ? How 

 many spermatozoids for each oospere or egg} 



11. Study the proembryo, from which the normal Chara plant develops as 

 a lateral bud. Draw and describe. Proembryos may be obtained by placing 

 plants with mature spores in a glass jar of water and keeping them over winter. 

 In the spring the embryos will be found at the bottom. 



12. Make a diagram showing the life cycle of Chara. Compare with Vau- 

 cheria. 



XXIX. Batrachospermnm mojiiliforme Roth. 



Class, Florideae. Order, Nemalionales. Family, Helminthocladiaceae. 

 Batrachospermum is an alga of considerable size which can be found attached 

 to stones in fresh water rivulets and creeks. 



1. Spread out the frond of the alga in water in a porcelain plate and sketch 

 the entire plant. 



2. Mount some of the branches in water, crushing them considerably under 

 the cover-glass, and sketch under low power. 



3. Under high power draw one of the lateral branches coming out from the 

 nodes. Note the oval cells and the bristle-like projections on some of the 

 terminal cells. 



4. In a young, main branch study the branches which pass down from the 

 base of the nodal branches and form a loose cortical layer. How does this 

 compare with the cortical layer in Chara ? 



5. Crush some of the older branches under the cover-glass by pressing and 

 rubbing carefully over the surface with the handle of the needle and study the 

 oogonia. These are situated on the lateral branches, and each consists of a 

 thickened hair-like process (trichogyne) and a bulbous base (trichophore) con- 

 taining the oosphere. Draw. 



6. Study the antheridia, which are single terminal cells, each of which 

 develops a single spherical male gamete (spermatium) without flagella. Draw 

 an antheridium and a free floating spermatium. 



7. Draw a oogonium which has one or more spermatia attached to the 

 trichogyne. 



8. Draw a sporocarp under low power. This is a spherical cluster of 

 branches which develops from the fertilized egg. 



9. Under high power draw a nonsexual carpospore at the end of one of the 

 branches of the sporocarp. 



1 0. From the foregoing study it will appear that Batrachospermum possesses 

 a sort of an alternation of generations. Besides this, it has another interesting 

 stage. When the carpospore germinates it gives rise to a peculiar filamentous 

 proembryo or protonema, formerly known as the chantransia stage, from which 

 the normal Batrachospermum plant develops as a lateral bud. This is a case of 



