128 
Proceedings of the Royal Society of Edinburgh. [Sess. 
precedes the formation of transverse walls, and we see forms in which both 
the constriction and the transverse walls are present. Again, the form of 
a diplococcus exactly resembles that of the present day, and the preserva- 
tion is so excellent here that one can note the fact that the transverse wall 
bears tlie same proportion in thickness to the outer wall that it does in the 
21 . 
Figs. 18-21. — Fossil Bacteria from the Gault (Folkestone). 
Fig. 18.— Bacillus I (Gault). 
Elongated threads : width, 1 /a ; length up to 100 /j. and more. xl266. 
Fig. 19.— Bacillus I (Gault). 
Shows rod splitting up into four daughter-rods. xl266. 
Fig. 20. — Bacillus II (Gault). 
Bacillus of approximately the same width as average modern bacillus, viz. 1 /u,. x 1266. 
Fig. 21.— Micrococcus I (Gault). 
a. Unicoccus. 
b. Diplococcus. Shows constriction in middle which precedes cell division. In the 
centre of each compartment are remains of cell contents. 
c. Diplococcus, showing transverse division wall and constriction. Cell walls are 
sharply contoured and in excellent state of preservation, x 1266. 
uase of modern cocci. The diameter of the coccus was 2|^-2f ju, which is 
slightly above the average found in modern cocci, though less than that of 
some of the members of the modern Coccaceae. In fig. 17 a there seem to be 
remains of cell contents. It appears as though the protoplasm had broken 
away from the cell walls and contracted to a greater extent than the cell 
walls. No traces of tri-cocci or multi-cocci were seen, neither were there 
indications of cocci which divided in three directions of space — Sarcina ; but 
one cannot doubt that further search will result in the discovery of groups 
allied to this class. 
