426 Proceedings of the Royal Irish Academy. 



bones ("Wood, jlilaealister, &c.). I have seen but one specimen ; it arose 

 from the bases of the second and third metacarpal bones, and took some 

 fibres from the adjacent part of the posterior annular ligament, and 

 gave off two tendons which went to the index and middle digits — each. 

 joining with the corresponding tendon of the long extensor. 



Extensor ossis metacarjji pollicis. — The tendinous end of this muscle 

 presents very frequent variations. I have seen the tendon double ; 

 the second slip going in one case to the trapezium; in two instances to 

 the abductor pollicis. A triple tendon occurred once : one had the nor- 

 mal attachment, the other two slips went to the trapezium, and to outer 

 edge of abductor pollicis respectively. A C[uratuple tendon existed in 

 one case : two of the slips went to the normal insertion, two to the tra- 

 pezium, and one to become fused with the extensor primi intemodii 

 pollicis. 



JExtensor primi internodii pollicis. — This muscle was completely 

 absent in one case ; and in two others sent an accessory tendinous 

 slip to the extensor secundi. 



Of the muscles of the thenar eminence few notable variations were 

 observed. 



AMiictor pollicis Irevis alter; abductor pollicis internus. — Of this 

 accessory bundle of muscular fibres — arising with the normal abduc- 

 tor and on its inner side — I have seen two examples. 



Adductor pollicis. — In a large number of cases (of which, indeed, I 

 kept no accurate record) the radial artery divided the muscle into two 

 parts, as has been specially described by Bischoff, who has given the 

 two divisions the names oi adductor pollicis ollig^uus, ojidL adductor polli- 

 cis transversus respectively. 



Abductor minimi digiti. — This muscle I have found arising by two 

 completely separate heads ; one from the pisiform bone, the second 

 from the anterior annular ligament. 



Lumbricales. — The first was absent twice in thiiiy-four subjects. 

 Both first and second were absent in another. 



Psoas parvus. — A remarkable specimen of this muscle was met 

 with last session. It had the usual origin ; but the insertion was into 

 the side of the cartilage between third and fourth lumbar vertebrae. 



Iliacus minor; ilio-capsularis. — Analogous to the subscapularis 

 minor in upper extremity. Aiises from anterior inferior spine and 

 ilio-femoral ligament, and is inserted, a little above the iliacus tendon, 

 into the spii'al line. 



Tensor xaginae femoris. — In one case the origin of the muscle was 

 three-quarters of an inch distant from the anterior superior spine of 

 the ilium. The only other variation I have observed is the great 

 difference in the length of its fibres in different subjects. 



Sartorim. — I once found inserted into the inside of the capsule of 

 the knee-joint. 



Adductor minimus (Henle) ; adductor quart us (Diemerbrock). — 

 This muscle is merely the upper and outer part of adductor magnus ; I 

 consider it worthy of separate mention because I have found it quite a 



