143 



carpal articulation, and formed a belly two inches in length, which 

 ended opposite the base of the first phalanx by again becoming 

 tendinous. This seemed an attempt at the digastric arrangement which 

 I have before described, and it has a very interesting point, namely— 

 that it shows a step towards the degradation of the perforated muscle 

 in the foot, as the modification in that region is merely the occurrence 

 of this change to all the tendons, with a suppression of the leg portion. 



9. In the leg of one female subject, the extensor digitorum brevis 

 sent a slip to the little toe, as well as to the four inner — an arrangement 

 which I believe to be one of very rare occurrence. 



As a supplement to the catalogue of muscular anomalies just 

 enumerated, we may naturally and with some interest consider the 

 light which it sheds upon the vexed question of the serial homologies 

 of the muscles in the different parts of the body, and we may consider 

 these in two groups — 1st, those of the limbs ; and secondly, those of the 

 trunk. 



The serial homology of the muscles of the upper and lower 

 extremities is a subject which primd facie appears much simpler than it 

 really proves to be when studied in detail; and I think a great deal of 

 confusion has crept into the subject from trying to reason exclusively 

 from the anatomical arrangements of one animal or class of animals. In 

 no single animal, be it man or saurian, do we find the muscles typically 

 arranged ; but the investigation of the myology of the limbs of 

 individuals of different races teaches us that the muscles of each limb 

 are built up after the model of a definite archetype ; but they teach us 

 equally plainly that in no individual animal do we find the typical 

 arrangement fully represented : both limbs show us modified muscles ; 

 and the question resolves itself into these parts — what type muscles are 

 there, and what representatives do we find of these types? This branch 

 of Comparative Anatomy began its systematic existence in the writings 

 of Vicq d'Azyr, although it was foreshadowed by others before that 

 time, and we may say of it truly, as he did, "Dans cette espece nouvelle 

 d'anatomie comparee on observe comme dans l'anatomie comparee 

 ordinaire ces deux caracteres que la nature parait avoir imprimes a tout 

 les etres, celui de la Constance dans le type et de la variete dans les 

 modifications. Elle semble avoir forme ces differences especes et leurs 

 parties correspondantes sur un meme plan qu'elle soit modifies a 

 1'infini." We may, for the convenience of further consideration, divide 

 the groups of muscles in every vertebrate extremity into the following 

 series : first, those of the basal joint of the limb ; secondly, those of the 

 shaft of the primal bone ; thirdly, those of the second, or ginglymus 

 joint ; fourthly, those of the metacarpal series ; and fifthly, those of the 

 digits. 



The comparative positions of the two limbs have been discussed 

 frequently, and many anatomists have argued from their interpretations 

 of bony arrangements as to the disposition of the muscles. Now, as the 

 bones are in function to some extent subsidiary to the surrounding soft 

 parts, we may find that a consideration both of the osseous and muscular 



