Dr. A. L. Herrera,

Secretaria de Agricultura y Fomento,

Direccion de Estudios Bilogicos,

7a Balderas num. 94, Mexico, D.F.



My dear Doctor Herrera:



Yesterday I sent you under separate cover a few articles relating to the osteology of the Diplodocus, which I infer from a previous letter which you wrote me, are not in the library of your Museum, and which will serve to throw light upon the structure of this huge beast.



Today I an sending you blue prints: A, of the plans which were used at Bologna, London, St. Petersburgh, La Plata, & c., in which the tail of the Diplodocus is mounted as it is in the Carnegie Museum, Fully estended; B, the blue print of the plan which we employed when mounting the specimen in Vienna where, owing to the limited space for exhibition, we were compelled to mount the tail of the specimen in a curved position, as indicated in the little sketch which I sent you some time ago, and which you have no doubt in your correspondence.  Permit me to remark, as I already have I think in one of my previous letters, that the material of which the tops of the bases are composed is left entirely to your choice.  In Bologna Senator Capellini employed Italian walnut, (Juglan); in Argentina they also use the wood of the Andean walnut, (Juglans).  Everywhere else the tops and sides were made of mahogany.  The side panels on the bases in London, Vienna, and elsewhere were not as numerous as they are represented in the plan, which was used in Bologna.  I do