457 



arises (which, however, was in this instance deficient), and shortly after 

 it was joined by a slip from the flexor digitorum sublimis. The con- 

 joined slip thns formed passed behind the ulnar artery, and terminated 

 in the flexor pollicis longus. 



12. The extensores carpi radialis longior and brevier are not un- 

 frequently the subjects of altered attachments and course : most usually, 

 however, their varieties belong to the class of anomalies by coalescence. 

 I have in my notebook the records of a very singular interchange 

 which occurred between the tendons of these muscles. In this subject the 

 tendon of the extensor longior, a short distance below its origin, divided 

 into two slips, one of which, becoming tendinous, passed off to unite 

 with a similar offshoot from the extensor brevior. The conjoined 

 tendon thus formed passed for a short course between the slips which 

 represented the typical muscles, and then bifurcated, each of the result- 

 ing tendons being inserted under cover of the normal insertions of the 

 type muscles, respectively, into the second and third metacai^pal bones. 

 This may be in some slight degree a representative of the mode of in- 

 sertion in the ornithorhynchus, where a single tendon terminates in 

 three slips for the three outer metacarpals ; but the peculiar double mode 

 of insertion is, to my knowledge, unexampled in the animal king- 

 dom. 



In another subject the extensor carpi radialis brevior was inserted 

 into the third metacarpal bone by three tendons. 



12. The triple insertion of the extensor ossis metacarpi pollicis I 

 have repeatedly noticed, but on several occasions, they have been ar- 

 ranged in a manner different from that usually described. 



Sometimes two of the fasciculi passed outwards to the first phalanx, 

 while the other band was connected to the trapezium, or to the 

 metacarpal bone, or to the short abductor pollicis. .Again, I found the 

 slips sent, one to the abductor, a second to the opponens, which also 

 was connected by a short recurrent band to the trapezium, while the 

 third was attached as usual to the metacarpal bone. 



13. The extensor secundi internodii pollicis I have commonly 

 (about once in every nine subjects) found with a double tendon — the 

 supplementary portion being inserted into the base of the first phalanx, 

 and lying internal to the normal tendon. 



14. The abductor minimis digiti I have found on two occasions pre- 

 senting an anomaly similar to number 14 in Mr. "Wood's paper ("Pro- 

 ceedings of the Royal Society," June, 1864), only that in my subjects 

 the deviating muscle was not the flexor brevis, but the abductor, which 

 arose by two heads — one a superficial and external, from the tendon of 

 the palmaris longus and fascia of the forearm, about an inch in one sub- 

 ject, and three inches in another, above the anterior annular ligament. 

 This portion crossed the ulnar artery and nerve, covering the flexor 

 brevis, from which it was quite distinct. The deeper or normal head 

 of this muscle united with the superficial in one case by fleshy fibres at 

 the wrist, but in the other by a tendon near the fingers, both being 

 inserted in common into the inner side of the first phalanx of the little 

 finger. 



