1865.] Mr. J. Wood Varieties in Human My ology. 389 



muscle. The other head was derived in the usual penniform way from the 

 indicial tendon of the perforans. The whole muscle was larger than 

 common, and was inserted in the usual way. 



The same hand presented also a double insertion of the third lumbricalis, 

 which was divided between the inner side of the medius and the radial 

 side of the ring-finger, and inserted in the usual way. The middle finger 

 is thus provided with a lumbricalis on each side. An exactly similar ar- 

 rangement to this was found in another subject, a female, on both sides. 



In a muscular male, the extensores radiales of the left arm exchanged 

 tendinous slips of considerable size. That from the longior was highest, 

 and joined the brevior just below the place where the latter gave off its 

 return slip to join the tendon of the longior at its insertion into the base 

 of the second metacarpal. Mr. Langrnore, a student of University Col- 

 lege, has lately written to the author to say that he has seen in a subject there 

 dissected, a muscle arising with the extensor carpi radialis longior, the 

 tendon of which, passing under that of the brevior, was inserted to its 

 ulnar side into the base of the middle metacarpal. These irregularities 

 are interesting in their bearing upon the occasional occurrence of the 

 extensor carpi raaialis accessorius before described. This muscle, how- 

 ever, is distinguished from all these by its insertion into the metacarpal of 

 the pollex, and its frequent connexion with the abductor in the manner of 

 the tendon of the extensor ossis metacarpi. 



In many feet of both sexes, examined during the session, were found 

 sesamoid bones developed in the tendon of the tibialis anticus, and 

 playing over a bursa on the internal cuneiform cone. In one, a male, a 

 strong distinct slip of tendon passed from it to join and strengthen the 

 inner division of the plantar fascia, being ultimately attached to the base 

 of the great toe. 



In many of the same feet, and in others, a sesamoid bone was likewise 

 found in the tendon of the tibialis posticus, placed to the inner side of, 

 and playing over, the scaphoid bone. Its relation to the occurrence of an 

 additional tarsal bone in this situation in the hinder limbs of the Arma- 

 dilloes and other Edentata is suggestive. The special muscle found at- 

 tached to it in these animals is produced apparently by a differentiation of 

 fibres of the tibialis posticus, similar to that which frequently occurs in 

 the tibialis anticus in the human subject, as shown in the author's last 

 paper read before the Society. 



In a small male foot (right) was found a slip of muscle revealing a 

 transitional formation towards that universal in the apes, and sometimes 

 seen complete in the human subject. A small slip of muscle from the 

 flexor brevis digitorum (fig. 6 6) is joined by a similar one, arising by a 

 tendinous origin from the outer part of the tendon of the flexor longus 

 (a). The two, after joining, result in a tendon, which instead of 

 forming a regular perforatus for the little toe, becomes blended with 

 that of the long or perforating flexor at the first phalanx, giving off slips 



VOL. XIV. 2 G 



