88 



286. Model of the pyramidal apical cell from a shoot 

 of Equisetum ; highly magnified. 



E. 161. 188S. Made by F. 8. Leach. 



287. Model of a stoma from a leaf; highly mag- 

 nified. 



E. 162. 1888. Made by F. S. Leach. 



The model can be separated into four parts to show the form 

 and relations of the two sausage-shaped guard-cells. 



288. Models illustrating the arrangement of the 

 fibro-vascular bundles in the stems of different types of 

 plants. 



Made by F. S. Leach. 



1. Fern (Osmunda). E. 155. 1888. 



2. (Aspidium). E. 158. 1888. 



3. Horse-tail (Equisetum). E. 157. 1888. 



4. Conifer (Juniperus). E. 152. 1888. 



5. Rammculacese (Clematis). E. 151. 1888. 



6. Palmacese (Palm). E. 159. 1888. 



7. Fern (Davallia). E. 153. 1888. 



8. Crucifere (Iberia). E. 154. 1888. 



9. Leguminosae (Phaseolus). E. 156. 1888. 



289. A model of Micrococcus Crepusculum, magnified 

 20,000 diameters, showing the form which appears in 

 certain boiled foods, such as potatoes. 



E. 32. 1884. Made by E. Brendel, Berlin. 



290. A model of Bacterium Termo, Duj. 3 the putrefac- 

 tion ferment ; magnified 10,000 diameters. 



E. 32a. 1884. Made by E. Brendel, Berlin. 



One model shows the ordinary condition of the organism, 

 another incipient segmentation, whilst in the third the segmenta- 

 tion has already taken place. 



291. A series of six models illustrating the life his- 

 tory of Bacillus subtilis Cohn., on four stands ; magnified 

 25,000 diameters. 



E. 326 to e. 1884. Made by E. Brendel, Berlin. 



a. The swarm-stage with two flagella. 



b. The full-grown Leptothrix condition, with incipient 



formation of spores. 



c. A free spore. 



d. Spore beginning to germinate. 



e. The spore which 'has already germinated. 

 /. Origin of new threads from the spore. 



