100 M. Brongniart on the Relations of the 
dener nor I have heard any voice.—[The large long-necked tor- 
toise fuffs like a cat very often. ] 
. I remain, dear Sir, yours very truly, 
Dr. Johnston. Parrick NEILL. 
My peEAR Sir, Canonmills, Feb. 25, 1845. 
The Phrynosoma, I regret to say, unexpectedly died about a 
week ago. I am not aware of having been able to make any ob- 
servations in addition to those I formerly communicated. 
We had a chamber made for it just over the entrance of the 
flue, and where the temperature was scarcely ever so low as 60° F., 
and often 70° and upwards: we kept a shallow saucer with water 
in the chamber, and always some Hypnum moss or foreign Ly- 
copodium laid over the saucer, so that the lizard could drink and 
could not overturn the vessel or spill the water. The creature 
often sat on the top of the moss. 
Dear Sir, yours very truly, 
Dr. Johnston. Patrick NEILL. 
XVIII.—On the Relations of the genus Noggerathia to Living 
Plants. By M. Avotene Bronentarr *, 
Tne difficulties in determining the relations of fossil plants to 
those now in existence have long been known. ‘The isolation of 
the different parts of a plant, and in most cases their imperfect 
state of preservation, which obliges the naturalist to be satisfied 
with the examination of characters which are frequently the least 
important, are the principal obstacles to this study. The more 
the plants, the remains of which are submitted to our investiga- 
tion, differ in their organization from those which are the con- 
stant studies of the botanist, so much the more difficult is the 
establishment of their analogies. The further we proceed in the 
series of ages towards the earliest geological periods, the further 
are we removed from the actual creation, and the greater do the 
differences between the living and fossil beings become ; this 
general law is well-established in the animal kingdom, and it is 
not less true for the vegetable world. 
Thus most of the fossil plants of the tertiary strata belong to 
eenera in actual existence, and merely present specific differences ; 
such are the pines, elms, birches, maples, walnut-trees, Nymphee, 
&e. eA 
Those of the secondary strata may undoubtedly almost always 
be referred to known families, but appear in most cases to re- 
quire the formation of new genera. 
Lastly, in the older strata, particularly m the coal-formations, 
* Translated from the Comptes Rendus for December 29, 1845. 
