64 Sheppard, on Colour in Organised Substances. 
rolled and truncated at each end. In section they show a 
core of osteo-dentine with very thick walls of cement. They 
are much rounder and bulkier teeth than those of the recent 
Micropteron. Some specimens show anteriorly fragments of 
a brighter denser substance, which I believe are the remains 
of the dentinal cap or nipple characteristic of ziphioid teeth. 
The infiltration of mineral matter in varying quantities into 
the differently constituted tissues of the tooth would readily 
cause their separation, and the double rolling and deposi- 
tion to which these crag mammalian remains have for 
the most part been subjected, would be very efficient in 
breaking off the small tip of the tooth. Figs. 3 and 4 represent 
of half the natural size two very large Cetacean teeth which I 
obtained some time since from the Red Crag. The first 
(fig. 3) is in section, and appears to have preserved a small 
cap of dentine surmounting the osteo-dentine and cement, 
which form the bulk of this very large tooth.* Fig. 4 is 
probably not the tooth of a ziphioid at all, but is remarkable 
for its large size. 
On an Example of the Production of a Colour possessing 
Remarkable Qualities by the Action of Monads (or 
some other Microscopic Organism ) upon Organised Sub- 
stances. By J. B. Sheppard, M.R.C.S.E. 
(Communicated by the Rev. J. B. Reade, F.R.S., F.R.M.S., &c.) 
(Read May 8th, 1867.) 
I will relate, as shortly as I can, the steps by which I 
became acquainted with the properties of the coloured liquid 
in the “ thousand-grain bottle. ”f The history is as follows : 
— On April 19th I went with two archaeological friends for a 
long ramble through West Kent. Our route lay through 
that district where the greensand crops out from under the 
chalk escarpment between Ashford and Maidstone. About 
* The chief interest of this specimen is in the preservation on its surface 
of a large amount of the fine sandy deposit in which it w r as imbedded, pre- 
viously to its deposition in the Red Crag-, it being like all the other Rhynchoceti , 
Carcharodons, &c.,of theRed Crag — already a fossil when the Red Crag sea and 
mollusca were existing. This fact has been unaccountably overlooked by 
some geologists, who wish to show that the Red and Coralline Crag were 
contemporaneous , or nearly so, with the Lower and Middle Antwerp Crags, 
where similar Cetacean remains occur in an unrolled condition, the Cetacea 
&c., having lived during that period, not during the Red Crag. 
f Shown at the Soiree of the Royal Microscopical Society, by the Rev. 
J. B. Reade, April 24th. 
