463 



very acute angles. In one of these subjects the lumbricales were arranged 

 in two sets : one group corresponded to the accessory or deeper tendons, 

 and these were connected with the third and fifth toes ; another series 

 was placed in connexion with the ordinary flexor tendons, and were 

 inserted into the second and fourth toes. This peculiar mode of arrange- 

 ment has not been before described. A minute and careful description 

 of these modes of union, by Mr. Turner, will be found in the " Trans- 

 actions of the Koyal Society of Edinburgh," vol. xxiv. (December 19, 

 1864). 



12. In the upper third of the arm of a female subject a small round 

 muscular bundle crossed over the brachial artery : it arose from the 

 lower border of the tendons of the latissimus dorsi and teres major 

 muscles (which were inseparably united), and ended below in the 

 tendon of the coraco-brachialis muscle. Its length was about two inches, 

 and it lay underneath the brachial aponeurosis. This slip resembles 

 some of those recorded by Dr. Struthers in the " British and Foreign 

 Medico- Chirurgical Review " for 1854 ; but was peculiar in that it com- 

 menced by tendinous fibres, which crossed the tendon of the latissimus 

 dorsi at right angles, and that its fibres ran, not transversely, but ob- 

 liquely downwards and outwards over the artery. 



Y. Varieties by segmentation, or the fission of normal muscles into 

 separate parts, are of frequent occurrence, and may indicate that the 

 muscle so divided is composed of several homologically distinct seg- 

 ments, which have coalesced, or else the splitting may be accidental, and 

 may arise from the atrophy or non-development of the natural connect- 

 ing fibres which ought to connect the severed portions. 



1. The pectoralis major was very commonly — indeed, in the majority 

 of cases — thus divided, the sternal and clavicular fibres being separated 

 by a deep and wide interval. The costal fibres were rarely as distinctly 

 isolated from the sternal portion as were the latter from the clavicular ; 

 and this condition I have seen in a pig, also in several monkeys. 



2. The upper portion of the serratus magnns I have likewise seen 

 perfectly distinct from the middle and lower parts of the muscle — a con- 

 dition which I have found in Cercopithecus and Cebns, where the upper 

 portion of the muscle is inseparably connected with the levator anguli 

 scapulas. 



3. The sterno-cleido-mastoid sometimes was similarly divided, the 

 spinal accessory nerve passing through the interspace between the two 

 nearly parallel bellies. These Meckel considers as the representatives of 

 two muscles — a sterno-mastoid and a cleido-mastoid — which he describes 

 as the cervical equivalents of the rectus and pyramidalis muscles in the 

 abdomen, and the antitheses of the splenii capitis and colli. 



4. The biceps flexor cubiti in a similar manner I have been, on two 

 or three occasions, able to separate throughout the whole extent of its 

 fleshy belly as far as its tendon, into two parts — thus showing the com- 

 posite nature of this muscle, and that it is most probably the represen- 



