the CMmpanzee and others of the Primates. 345 



in the specimen described by Prof. Hnmplny [he. cit. p. 266), 

 as in his case it crossed tlie process to the great tuberosity of 

 the humerus. In Dr. Wilder' s specimen it was inserted into 

 the coracoid on the left and into the humerus on the right. 

 Prof. Humphry remarks that this is the most common qua- 

 drumanous arrangement ; but though this is quite true as 

 regards the humeral or capsular insertion of the pectoralis 

 minor, yet it is, in my experience, far from common to find a 

 lesser pectoral in monkeys crossing the coracoid process. I 

 I have found the lesser pectoral thus inserted either into the 

 greater tuberosity or the capsular ligament in Macacus 7-hesus, 

 cynomolgus^ sinicus.^ nemestrinus^ Inuus sylvanus^ Cercopi- 

 tliecus ruber and sahanis^ CoJohus, Cehus apeUa and cajnicimis, 

 Cercocehus fuUginosuSj Cynocephalus porcarius ^ and others. 



Above the lesser pectoral on the left side was a small muscle, 

 somewhat similar to a remarkable human anomaly described 

 by Prof. Gruber, of St. Petersburg, the tensor semivaginge 

 humero-scapularis ; it arose from the cartilages of the third 

 and fourth ribs, and, passing outwards over the tendon of the 

 lesser pectoral, was inserted into the capsule of the shoulder, 

 under cover of the deltoid. In the Gorilla, Prof. Duvernoy 

 found a second lower part of the lesser pectoral inserted into 

 the short head of the biceps ; and the same was seen by Prof. 

 Wyman, No such arrangement existed in our Chimpanzee : 

 the little tensor above described seemed at first sight like 

 a second lesser pectoral ; but its insertion was superficial to 

 the seat of the normal attachment of a prolonged lesser pec- 

 toral tendon, if such had been present. The subclavius was 

 normal, and the costo-coracoid membrane overlying it was, as 

 usual, split by the pectoralis-minor tendon at its outer end. 

 This is an extremely common human arrangement. The 

 ligaments of the shoulder-joint are very like those of man, 

 but all the accessory ligaments are weak : this is not the case 

 in all monkeys ; for I have found both the gleno-humeral 

 ligament (Flood's) and the inferior ligament of Humphry veiy 

 strong and cord-like in Cercopitliecus ruber. (A specimen 

 showing these I have placed in the Museum of the Royal 

 College of Surgeons, Dublin.) 



A very slight rudiment of a coraco-brachialis brevis was 

 present, a muscle which has not been noticed by Wilder, but 

 was seen by Vrolik ; the rest of this muscle was split by the 

 musculo-cutaneous nerve, and extended down rather further 

 than usual on the arm. The coraco-brachialis brevis I have 

 found in all the Quadrumana which I have dissected, either 

 as a tendinous or muscular slip ; it seems much more constant 

 in them than in man. 



