MYOLOGY 47 



Thence the origin is from the dorsal fascia for some 25 mm. 

 additional. Passing to the axillary region it converges to 

 a stout tendon (not in common with the teres major) which 

 is inserted upon the lateral spine of the humerus. From 

 the ventro-distal portion of the latissimus arises the epi- 

 trochlearis. 



In Teonoma origin extends for about 5 mm. longer, with 

 the ventral portion of the belly correspondingly broader. 



The innervation of this muscle is by a branch from the 

 brachial plexus — undoubtedly the thoraco-dorsal nerve. 



Second layer of the superficial, secondary, back muscles 

 includes the 



Mm. rhomboideus anticus occipitoscapularis 



rhomboideus posticus atlantoscapularis 



M. rhomboideus anticus (figs. 6, 29). While the 

 posterior rhomboid corresponds to a considerable degree 

 with the rhomboideus major of human anatomy, it is the 

 smaller division in Neotoma. The portion here termed 

 anticus is much the larger, and in its attachments does not 

 so closely resemble the usual rhomboideus minor. Hence, 

 terms indicating position seem to be more applicable in 

 the present instance. It has origin from the middorsal 

 line extending from the spine of the axis to the first thoracic 

 vertebra. The muscle converges somewhat, passes along 

 the medio-dorsal border of the scapula and is inserted by 

 both muscle and tendon fibers beneath the insertion of the 

 rhomboideus posticus. This insertion extends to a point 

 at right angles to the border and mediad of the spine. 



In Neotoma insertion extends hardly at all upon the 

 scapular border but rather it is practically confined to an 

 area upon the scapula at right angles to the border and 

 opposite the spine. In Teonoma the cranial portion is 

 narrower and weaker, but the more caudal part of the 

 origin is stronger, being practically continuous with, and 



