1884.] MR. G. K. DOBSON ON CAPROMYS MELANURUS. 239 



clavicle as far as the origin of the cleido-mastoid, under cover of the 

 levator claviculce. 



The clavicular part of this muscle evidently corresponds to the 

 cleido-occipital which is united with it. 



Trapezius posticus has a very extensive origin, arising as far 

 forwards as the posterior origin of the tr. anticus (with which it 

 may almost be said to be continuous), and extending to the com- 

 mencement of the lumbar aponeurosis, quite covering tlie anterior 

 half of the latissimus dorsi. 



Rhomboideus anticus and rh. posticus are represented by a single 

 muscle arising from the inner third of the occipital crest and from 

 the centre line of the neck, to the first and second dorsal spines. 

 The anterior half of the muscle is very thin, the posterior much 

 thicker ; all the fibres are inserted into the internal and postero- 

 internal border of the scapula. 



Serratus magnus is overlapped by the posterior margin of the 

 levator angulce scapula. It arises from the cartilages of the first to 

 the sixth ribs and is inserted as usual. 



Levator angulce scapula arises from the transverse processes of 

 the third to the seventh cervical vertebra?, and is closely connected 

 throughout its origin with the scalenus medius. 



Scalenus anticus absent, as shown by the position of the brachial 

 plexus. Sc. medius (fig. 1, sc.ni) and sc. posticus appear to be united ; 

 they are inserted into the cartilages of the fourth to the sixth ribs. 



Muscles of the Fore Limb. 



Pectoralis major (fig. 1, p-p") arises in four parts — three 

 sternal from the whole length of the sternum and aponeurosis of the 

 external oblique, and one clavicular. Of the sternal the anterior 

 (p') arises from the auterior extremity of the manubrium sterni and 

 as far back as the middle of the sternum under cover of the origin 

 of the sterno-facialis, and, uniting with the clavicular part, is 

 inserted with it into the middle of the shaft of the humerus along 

 with the deltoid ; the middle part arises behind the preceding 

 as a strap-shaped muscle (p"), which is inserted under cover 

 of it into the shaft of the humerus and into the internal tube- 

 rosity ; and the posterior (p'"), broader, from the last bone of 

 the sternum and from the aponeurosis of the external oblique 

 muscle, is inserted under cover of the middle part into the internal 

 tuberosity higher up. The clavicular part arises from the outer 

 third of the clavicle, becomes connected with the anterior division of 

 the sternal part below, and, above, with the lower margin of the 

 deltoid, and is inserted as above described. 



Pectoralis minor (fig. 1, /j' v ). — This is represented by a com- 

 pletely separate strap-shaped muscle arising from the cartilages of 

 the third to the sixth ribs, and inserted into the outer third of the 

 clavicle and acromion under cover of the origin of the clavicular 

 part of the pectoralis major. This is precisely as we find it in Dasg- 

 procta cristata. 



Deltoid arises from the acromion process (being connected by its 



