155 



supplemental function, namely, the extension of the metacarpal bone of 

 the thumb, it is mo dined into the extensor ossis metacarpi pollicis. 

 We may thus tabulate the muscles of this group : — 



The insertion of the last-named is one of the most variable points in 

 human anatomy, a very good evidence that it is not a typical attach- 

 ment. 



The third, or finger-supplying muscles are very complex in character, 

 but may easily be reduced into certain typical series. Firstly, to this 

 class I would refer a set of fascial muscles, represented in the arm by 

 palmaris longus brevis and accessorius. To the first of these types we 

 refer the plantaris of the lower limb, because, although even in the 

 human embryo the tendon has' no connexion with the plantar fascia, 

 yet in many of the lower animals its fascial connexion is distinct and 

 decided. It is no argument against the correspondence of these muscles 

 that in the arm its attachment is to the inner condyle, and in the leg of 

 the outer, for the attachment is one of convenience of action and not of 

 type ; for there is no actual inner condyle to the femur similar to the 

 process so named in the humerus, and the muscles which are regular 

 in the latter are errant in the former, none but the pronator preserving- 

 even a shadow of its typical place. The second muscle, or the palmaris 

 accessorius, a protean muscle in the arm typical in being on the hypo- 

 thenar side of the proper palmaris, and being connected most commonly 

 to some of the short flexor muscles of the hand, is represented in the 

 lower limb by the flexor accessorius of Wood and Turner springing from 

 the deep tibial fascia, and inserted into the musculus accessorius of 

 flexor tendons (Wood on Anomalies, " Proceedings of the Eoyal 

 Society," vol. xiii., p. 302. Turner on Variability in Human Struc- 

 tures, " Transactions of the Eoyal Society, Edinburgh,'' vol. xxiv., 

 p. 184). There is another muscle on the back of the ankle, de- 

 scribed by Gantzer, Hyrtl, and others, and attached to the deep layer 

 of the annular ligament or to the calcaneum directly, and springing 

 from the popliteal fascia, from the linea poplitea or tibial fascia. It is 

 possible that this, the tensor fascise plantaris of Wood may be another 

 form of the same type not at all improbable, considering the variations 

 which it exhibits in the forelimb. The third of the fascial group, or 

 palmaris brevis, is a true hand muscle, and will be considered as such. 

 Of these, I know of no true antitheses, as the dorsal aponeuroses both 

 in pes and manus are weak, and do not require special tensors. 



The second of the digital group of muscles consists of a flexor and 

 extensor series for the second phalanges of each finger. These in the 

 forearm are represented by the flexor sublimis digitorum, and the 

 extensor communis digitorum. In the leg they are typified by the flexor 



E. I. A. PEOC. VOL. X. Y 



Supinator longus, 



Pronator teres condyloid, 



Pronator quadratus, 



Pronator teres coronoid, 



Supinator brevis, 



Extensor ossis metacarpi pollicis, 



External head of gastrocnemius. 

 Internal head of gastrocnemius. 

 Peroneo-calcanean. 



Tibial head of soleus. 

 Popliteus. 



Extensor ossis metatarsi hallucis. 



