Knott — On Abnormalities in Human Myology. 421 



claded that it is really made up of four distinct parts, to which he gives 

 the respective names of coraco-radialis, coraco-ulnaris, gleno-radialis, 

 and gleno-ulnaris. The two first named form the short head, while the 

 union of the third and fourth segments forms the long or glenoid por- 

 tion. Although it may be rather difficult for most anatomists to agree 

 entirely with his views, a careful consideration of them certainly tends 

 to throw a good deal of light on the peculiarities of its variations. 



Coraco-radialis. — Alone, is present in Orycteropus capensis, rhino- 

 ceros, echidna, frog, toad, lizard. 



Coraco-radialis and coraco-ulnaris. — In emys, chameleon. 



Coraco-radialis and gleno-uhiaris. — In marsupialia, both muscles 

 being quite separate. 



Gleno-radialis. — Alone, in nycto-pithecus, stenops, talpa, horse, 

 ruminantia. 



Gleno-ulnaris. — Alone, in Hyrax capensis, rodentia. 



Gleno-radialis and gleyio-ulnaris. — In pig, monotremata. 



Doubling of the heads. I have observed two examples of duplicity 

 of the long head, and one of that of the short. 



The two heads of the muscle I have seen separate for the whole 

 length of its course. The long head I have found completely absent 

 in three cases, and the short head in one. The semilunar aponeurosis 

 I have found completely absent in one case. I have twice found an 

 accessory sHp from the tendon of the pectoralis minor going to the 

 short head. An accessory slip from brachialis anticus to biceps I 

 have found in three cases of forty-nine subjects, in which these 

 muscles were carefully examined. An additional head between coraco- 

 brachialis and biceps I have found present five times in the same 

 series of bodies. This nearly agrees with the results of Wood and 

 Macalister, who make its relative frequency to be one in ten. In one 

 case I have found two supernumerary heads arising in this region. 

 The upper came directly from the insertion of the coraco-brachialis, 

 from which it arose by a tendinous slip. The other came from a 

 point about an inch lower down, and was adherent to the adjacent 

 margin of the brachialis anticus. Its origin was entirely fleshy. An 

 additional origin from the great tuberosity I have seen in one case. 

 It has also been described by Meckel and Macalister. Under the 

 denomination of supernumerary attachments of the biceps must also 

 be classed the following varieties, which have been described under 

 separate names : — 



Brachio-radialis (Gruber, Theile, &c.). — Arises from the humerus 

 between the insertion of the deltoid and the origin of the supinator 

 longus, and passing down close to the outer margin of the biceps, but 

 distinctly separate from the latter, to be inserted with it into the tube- 

 rosity of the radius. I have found this muscle extremely well deve- 

 loped in two instances, but it adhered very intimately to the lower part 

 of the muscular portion of the triceps, and almost inseparably to its 

 tendon. 



Brachio-fascialis ; hrachialis accessories; supinator Irevis accessorius 



2N2 



