452 APPENDIX. 



fied portions of the two first divisions, but principally of the 

 second. 



Thus the first division consists of — 



a. A layer lining the harmal arches. 



b. Pre-vertebral muscles. 



c. Such pre-vertebral muscles as are attached to the limbs. 

 1 The second division consists of — 



a. Muscles of so-called dorsal group. 



b. Intercostal muscles. 



c. Recti abdominis. 



d. External and internal oblique muscles. 



e. All the muscles of the limbs, except those derived from the 



first division. 



/. Cutaneous muscles. 



The third division therefore, although apparently distinct, and 

 conveniently considered as such, is in fact derived from the first 

 and second divisions. 



IV.— NOTES ON THE MORPHOLOGY OF THE MUSCLES 

 OF THE LIMBS.— June 15, 1858. 



If the human femur and humerus be compared together, as 

 observed from the front of each, it will be perceived, that while the 

 surface of attachment of the brachialis anticus extends from the 

 outer to the inner humeral ridges, up as far as the lower part of the 

 insertion of the deltoid, inclosing the attachment of that muscle by 

 its bifurcation, the surface of attachment of the homologous muscle 

 in the thigh extends from each lip of the linea aspera and as far up 

 as the intertrochanteric ridge. From this enormous extension of 

 that muscular mass, termed vastus externus, vastus internus, and 

 crureus, the homologue of the brachialis anticus, all the other 

 muscles attached to the thigh-bone are attached to its trochanters 

 and condyles, and to the space enclosed between the lips of the 

 linea aspera. The comparison, therefore, of the characteristic con- 

 figuration of the humerus and femur, or, in other words, the serial 

 homology of their processes, surfaces, and edges, must be determined 

 by a careful comparison of the corresponding or homologous mus- 



