1899.] THE MYOLOGY OF THE EDENTATA. 325 



Cerv. Tr. Procs. Ribs. 



Cijclothurus (17) 2-7 1-8 



(18) 5-7 1-7 



(20) 5-7 1-7 



(21) 5-7 1-7 



Dasypus (22) hinder C. V. 1-8 or 9 



„ (24) 5-7 1-7 



Manis (29) 1-7 1-7 



„ (30) 1-7 1-7 



„ (32) 2-7 



„ (33) 2-7 1-6 



Orycteropus r35) 2-7 1-8 



(3fi) 2-7 1-8 



(37) 2-7 1-8 



From the foregoing it will be seen that the neck portion of the 

 muscle (the levator anguli scapulae of human myology) is either 

 absent or feebly developed in the Brady podidce. In Tamandua 

 (14) and two specimens of Manis (29, 30) it is described as arising 

 from the atlas, but past experience makes us think that in these 

 cases the rhomboideus profundus is incorporated with the serratus 

 ventralis colli. In some cases, e. g. Cyclothurus, the cervical, 

 anterior and posterior thoracic origins may remain distinct as far 

 as their insertion, and the muscle may then consist of three 

 portions, as it more or less does in Man. In other cases, e. g. 

 Dasypus (22), the cervical and thoracic portions may form two 

 separate sheets, while in many instances the whole muscle forms 

 one continuous plane. It may be added that on the whole the 

 muscle is one of great strength, exceeding in this respect the 

 condition met with in most of the mammals examined by us, 

 also that the scapular insertion often takes the form of two 

 strong bundles attached to a triangular portion of bone at the 

 caudal and cephalic ends of the scapula respectively, the part 

 between, though continuous with these two bundles, being 

 comparatively thin. 



Pectorales. — The pectoral mass in Edentates, as, indeed, generally 

 amongst the Mammalia, is exceedingly hard to classify, for the 

 greater the amount of available material, the more difficult does the 

 generalization become. We feel that the only way to do justice 

 to the subject would be to repeat the various descriptions in 

 extenso ; but as this is hardly possible, we shall content ourselves 

 with making what generalization we can. We believe that a 

 typical pectoral has superficial and deep manubrial and superficial 

 and deep gladiolar plaues, that there may be a claviciUar portion 

 and an abdominal sheet or pectoralis quartus arising from the 

 linea alba, that one or more bundles may rise from the anterior 

 ribs deep to the gladiolar fibres, and that these may be described as 

 a pectoralis minor. In Bradypus we have six descriptions, no two 

 of which agree. Macalister and Mackintosh failed to find any 

 abdominal portion or anything representing a pectoralis minor. 



Pboc. Zool. Soc— 1899, No. XXII. 22 



