294: Royal Society :— 
the Rhynchophora manifested by the transfer of a function 
from the posterior to the anterior part of the body, and the 
linear extension of the latter, in accordance with this “ change 
of base.” 3 
The principles of classification of Rhynchophora, and their 
division into families, will be discussed in a subsequent memoir. 
It is, however, proper to observe that the peculiar construction 
of prothorax above described as characteristic of the Rhyncho- 
phora is not exhibited in the Bruchide, which family, as ob- 
served by Lacordaire (Gen. Col. vii. 600) should be viewed as 
closely related to, if not actually a portion of, the great family 
Chrysomelide. | 
PROCEEDINGS OF LEARNED SOCIETIES. 
ROYAL SOCIETY. | 
June 20, 1867.—Lieut.-General Sabine, President, in the Chair. 
‘On some Elementary Principles in Animal Mechanics.” By 
the Rev. Samugen. Haveuron, M.D., Fellow of Trinity College, 
Dublin. 
There are some elementary principles in anima] mechanics 
which are so natural that they may be assumed as probable, and 
as such, have not received from observers the attention they really 
deserve. 
Among these principles I select for illustration the two follow- 
ing: — 
i. The force of a muscle is proportional to the area of its cross 
section. 
i. The force of a muscle is proportional to the cross section of 
the tendon that conveys its influence to a distant point. 
i. In order to test the first of these statements, I made a careful 
examination of the cross sections of the muscles that bend the fore- 
arm and leg, in a very finely developed male subject, with the 
following results :— 
Neglecting the slight effect of the supinator radii longus in 
flexing the forearm, I found the cross sections of the biceps 
humeri and brachieus to be as follows :— 
Cross section. 
1. Bicepsphumert «sw. ww TOA oe i. 
2: RVGCREOUE Cai ow oo AS ee 
3190 
. The cross sections of the muscles that bend the leg were found 
to be in the same subject :— 
