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finger. I have likewise seen three tendons arising from a common 

 muscle, one of which passed to the fourth finger, and was continuous 

 with the extensor tendon of that digit opposite the end of the first pha- 

 lanx; the other pair of tendons were, as usual, distributed to the little 

 finger. This arrangement I have likewise found in a species of Cebus. 



13. The solseus was in one subject doubled ; the accessory or second 

 portion lying under cover of the normal muscle, and connected to the 

 deep-seated surface of the tendo Achillis. 



14. Two perfectly distinct planes of fibres I have been able to detect 

 in the glutseus maximus on several occasions, especially along the infe- 

 rior border of the muscle : these were separated by a cellular lamina. 



III. Under the third head I place all those irregularities which arise 

 from the presence of additional origins, supernumerary tendons, unusual 

 insertions orrelational deviations from the ordinary arrangement of parts; 

 and these, as might be supposed, constitute the most numerous group of 

 muscular anomalies. They may be the results of original abnormal 

 development, or the products of disease or injury . The latter forms 

 I have, however, excluded as far as possible from my list, as they can- 

 not possess much value in comparative anatomy. I have found illus- 

 trations of this class involving the following muscles : — 



1. Latissimus dorsi. In many cases I have found this muscle to 

 be errant either in its origins or insertion. The former have been ex- 

 tended as far upward as the fourth dorsal spine, or have not reached 

 beyond the first lumbar vertebra, or have been attached to the inferior 

 angle of the scapula ; and the latter I have seen sometimes sending a 

 considerable accessory slip from its lower border into the fascia of 

 the arm. This band attains a considerable degree of development in 

 Cebus, and other monkeys. A portion of this tendon is often continued 

 into the long head of the triceps, and this I have found to occur about 

 three times in every thirty subjects. I have also seen the long tendon 

 of the triceps taking an origin more or less extensively either from the 

 lower border of the latissimus tendon alone, as in Cebus, or from it and 

 teres major combined. 



Yery much more rarely a fascial expansion, or even a musculo- 

 tendinous slip, has passed from the lower border of the latissimus dorsi 

 down as far as the olecranon process ; this we find to exist in the 

 gibbon, in Ateles, Cynoeephalus, and many others of the Quadrumana. 

 A similar portion exists in the horse ; and a muscle somewhat corre- 

 sponding I have traced in the pig, running from the inferior angle of 

 the scapula to the fascia on the inner side of the limb, over the triceps. 

 In many of the instances among the Quadrumana, where this muscle 

 exists as a supplement to the triceps, it is quite separate from that 

 muscle, even to its insertion ; and it is not improbable that it may be the 

 fore-limb homotype of the sartorius muscle, as in both cases the muscles 

 are superficial to the rest of the extensor mass, in both instances placed on 

 the extensor aspect of the limb, and both usually run from without in- 



B. I. A. PROC. VOL, IX. 3 O 



