coNTKiP.r'rroxs to tiik cvtui.ogy of the uactkuma. 499 



EXPLAXATIOX OF PLATES 16-19, 



Illusti'ating Mr. C. Clifford Dobell's '•' Contributions to the 

 Cytolog-y of the Bacteria." 



[All the figxires are drawn from fixed and stained organisms undei- 

 a Zeiss 2 mm. apochromatic oil-immei-sion (aperture ViO) with the 

 aid of compensating oculars 6, 8, 12, and 18. The magnification of all 

 figures is the same, and is approximately 2000 diameters. The figures 

 are in no way diagi-ammatic. They are accurate representations of the 

 actual appearances ohserved.] 



PLATE 16. 



Figs. 1-20 are from wet film preparations of the blood of Sacco- 

 b ranch us fossilis, fixed with osmic vapour followed by absolute 

 alcohol, and stained with Giemsa's stain. 



Figs. 1-10, 12 and 14. — Bacillus saccobranchi n. sp. 



Fig. 1. — Short Bacillus, with nucleus in the form of a slightly Ijent 

 and varicose filament. 



Fig. 2.— Two Bacilli with nuclei in the form of twisted zig-zag or 

 spiral filaments. 



Fig. 3. — Bacillus with nucleus in the form of fragments of a zig-zag 

 filament. 



Fig. 4. — Long Bacillus containing a long varicose zig-zag or spiral 

 nuclear filament. (Nucleus of spirogyra type.) 



Fig. 5. — Large Bacillus in which the nucleus is in the form of 

 granules and irregular short, curved, bent, and branched filaments. 

 (Irregular type of nucleus.) 



Fig. 6. — Large Bacillus with nucleus partly in the form of an irregular 

 zig-zag or spiral filament and partly in the form of irregular l^-anched 

 masses — connected with one another. 



Fig. 7. — Two short Bacilli with irregular nuclei. 



Fig. 8. — Large, slightly ciu-ved Bacillus, with nucleus in the form of 

 a broken varicose zig-zag or spiral filament. 



Fig. 9.— Bacillus with nucleus of irregular type. A part of the 

 nucleus shows a very distinct reticular aiTangement. 



Fig. 10. — Bacillus with nucleus of chromidial type. 



Fig. 12.— Bacillus with nucleus in the form of a thick varicose 

 filament. 



