PLATE 6. — Coiifervoidese.— Crystals. 



Figure 



1. Cosmarium margaritifer'wn, Turp. ; conjugating pair with imperfect sporange. 



2. C. BotrytiSy Bory ; conjugating pair with sporange, enveloped in jelly. 



3. A. Closterium acerosum, Schrank. a, b, c, different stages of conjugation ; 



dy frustules apparently produced from a sporange. 



3. B. Closterium LunulayMXiW..; the contents converted into globular bodies. 



4. Fragilaria penicillatai Lyngb. a and b, successive stages of conjugation. 



5. A. Surirella bifrons, Ehr. ; conjugating pair, vsdth intermediate large new 



frustule. 



5. B. Surirella hifrons, Ehr., with the contents converted into globular bodies. 



6. Eunotia turgida^ Ehr. «, 6, c, c?, e, successive stages of conjugation producing 



pairs of new frustules. ^^ 



7. Melosira (Aidacosira) crenulata, Thw. «, filament with two conjugating pairs 



of cells and perfect sporangial frustules ; b and c, large filaments produced 

 by sporangial frustules. 



8. Melosira varians, Ag. a, small filament producing sporangial frustules by con- 



jugation ; 6, large filament developed from sporangial frustules. 



9. Orthosira Dickiei, Thw. Successive stages of production of sporangial frustules 



after conjugation. 



10. Pinnularia viridisy W. Sm., with the contents converted into globular bodies. 



11. Pediastrum gramdatum, Ktz. «, a frond with most of the cells empty, three 



full, and the contents of another swarming out as zoospores ; b, c, d, swarm of 

 zoospores producing a new frond. 



1 2. Crystals of sugar of milk. 

 13. 



indigo, sublimed. 



oxalate of soda. 



sulphate of lime. 



phosphate of lime. 



sulphate of strontia. 



allantoin. 



antimoniate of soda. 



protoxide of antimony. 



butyrate of baryta, a, rapidly, 6, slowly formed. 



hydrofluosilicate of baryta. 



sulphate of baryta, a, precipitated from concentrated, b, from very 

 dilute solution. 



14. 

 15. 

 16. 

 17. 

 18. 

 1*. 

 2*. 

 3*. 

 4*. 

 5*. 

 6*. 



7*. 



carbonate of potash. 



