1868.] Mr. J. Wood on Variations in Human Myology. 



503 



and normal in the same arm, and fusiform in the opposite or right arm. 

 In both the sex was female, and the muscle was found in the left arm 

 only. In the 8 instances previously described by the author the sex in 7 

 was male ; and in all, the muscle was found in the right arm only. The 

 latter peculiarity was also present in 2 specimens, of which notes have been 

 kindly forwarded by Mr. Macalister of Dublin, one of which was inserted 

 into the third metacarpal and the other into the annular ligament. In 

 a note sent to the author in March last, the same excellent observer fa- 

 voured him with a description of a peculiar arrangement of the muscle which 

 he had found in a female in the left arm only. The muscle arose by two 

 heads, viz. the more usual one from the radius between the flexor sublimis 

 and flexor longus pollicis, and the other, flat and aponeurotic, from the 

 internal condyle of the humerus. These joined in a muscular belly 4 inches 

 long, which lay deeper than that of the flexor carpi radialis, and outside 

 of the flexor longus pollicis, and was inserted by three slips of tendon into 

 the deep surface of the annular ligament. The palmaris longus was also 

 present, and normal in this case. 



23. Palmarislo7igus. — In three males (Nos. 1, 6, & 15) this muscle and 

 its tendon were both double, in the first two in the left arm only. In 

 the last it was found in the right arm only— the supernumerary muscle being 

 almost median and fusiform in shape, and the tendon of insertion reaching 

 only to the annular ligament. In both arms of a male (No. 17) its tendon 

 was split up into several parts, all inserted into the annular ligament closer 

 than usual to the scaphoid. In both arms of No. 16 its belly was fusi- 

 form and nearly median, and its tendon of insertion gave off a slip to the 

 origin of the abductor pollicis. In the left arm of the females (Nos. 31 & 

 34) the muscular belly was also fusiform and median in its position. In 

 the latter, the tendon of insertion was double. In four, all females, the 

 palmaris was found entirely wanting — in No. 28 on both sides, in Nos. 

 20 & 31 in the right arm only, and in No. 36 in the left only. In the 

 right hand of the last, the pahiaris brevis was also absent. No slip of 

 substitution was found in any of these instances. In the right arm of the 

 male (No. 13), and in the left of the female (No. 29), the only representa- 

 tive of this muscle was a feeble rudimentary tendinous slip. 



Out of 102 closely observed subjects, viz. 68 males and 34 females, 23 

 have presented abnormalities of this muscle. In 7 of these they have 

 varied in the two arms, presenting altogether 31 instances; 6 were double 

 muscles, and 3 double tendons ; of these, in 7 males and 2 females, 1 was 

 in both arms, 2 in the right, and no less than 6 in the left arm only. It 

 has been altogether absent in 9 instances, and rudimentary in 2, viz. in 4 males 

 and 7 females; of these, 4 were in both arms, 4 in the right, and 3 in the 

 left arm only. The number of absent muscles was thus nearly double in 

 half the total number of females, giving a proportion of 4 to 1 of fre- 

 quency of absence in this sex. In 5, viz. 3 males and 2 females, the mus- 

 cular belly was median or inverted, in 2 on both sides, 2 in the right arm, 



