A Class List of Preparations 291 



CYANOPHYCEAE (SCHIZOMYCETES) 



4. Oscillatoria. Put living material into 10 per cent glycerin and allow 

 it to concentrate. 



5. Tolypothrix. Use the Venetian turpentine method. Should show 

 heterocysts, hormogonia, and false branching. 



6. Nostoc. Venetian turpentine method. 



7. Wasserbluthe. The principal forms in this material are: 



a) Coelosphaerium Kutzingianum. Colonies in the form of hollow 

 spheres. 



b) Anabaena gigantea. Filaments straight. Preparations should show 

 vegetative cells, heterocysts, hormogonia, and spores. 



c) Anabaena flos-aquae. Filaments curved. Stain on the slide and 

 mount in balsam. 



8. Gloeotrichia. Smear on the slide, stain in safranin and gentian- violet, 

 and mount in balsam; or use the Venetian turpentine method, staining 

 in Magdala red and anilin blue and crushing under the cover-glass. 



ALGAE 

 CHLOROPHYCEAE 



9. Volvox. Use the Venetian turpentine method. If paraffin material 

 is available, cut 5 /u, in thickness and stain in safranin, gentian-violet, 

 orange. 



10. Scenedesmus, Let a drop containing the material dry upon the slide, 

 stain, and mount in balsam. 



11. Hydrodictyon. Use the Venetian turpentine method. 



Each preparation should contain pieces of old and of young nets, and 

 also at least one young net developing within an older segment. The great- 

 est care must be taken not to injure the older segments while arranging the 

 mount. 



12. Ulothrix. Use the Venetian turpentine method. Each mount should 

 show various stages in the development of spores and gametes. 



13. Oedogonium. Stain in Magdala red and anilin blue and mount in 

 Venetian turpentine. 



14. Coleochaete. Stain in Delafield's haematoxylin and mount in balsam. 



15. Cladophora. Stain some in iron-haematoxylin and some in Magdala 

 red and anilin blue. Mount both together in Venetian turpentine. 



16. Diatoms. Make mounts of the frustules and also stained preparations 

 showing the cell contents. 



17. Desrnids. Make mounts of available forms. Use the Venetian turpen- 

 tine method if material is sufficiently abundant. 



18. Zygnema. Stain in iron-haematoxylin and mount in Venetian turpen- 

 tine. 



