100 M. Brongniart on the Relations of the 



dener nor I have heard any voice. — [The large long-necked tor- 

 toise /w^5 like a cat very often.] 



'tiiii'vi; >5>v..sv; I remain, dear Sir, yours very truly, 



Dr. Johnston. Patrick Neill. 



My DEAR 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. 



.i ,iioi3/mrj 1! I^ear Sir, yours very truly, ,, 



Dr. Johnston. ,, , ^ , .m' Patrick Neill. 



XVIII. — On the Relations of the genus Noggerathia to Living 

 Plants. By M. Adolphe Brongniart *. 

 The 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 ^o 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 

 genera in actual existence, and merely present specific differences; 

 such are the pines, elms, birches, maples, walnut-trees, NymphcecSy 

 &c. 



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 in the coal-formations, 

 * Translated from the Comptes lieiidas for December 29, 1845. 



