48 THE MYOLOGY OF THE RAVEN. 



above the bifurcation of the bronchi, on the lateral 

 aspect of the trachea. It ascends the side of the trachea 

 for its entire length, as a narrow ribbon of muscle closely 

 attached to the rings, until it arrives near the superior 

 larynx, when it spreads out like a fan, and its faint and 

 delicate fibres attach themselves to the side of the 

 upper end of the windpipe. Contraction of this pair 

 of muscles must shorten the trachea by closely ap- 

 proximating the upper and lower borders of its rings. 

 It also gives some support to this tube by acting as a 

 brace to its sides. 



31. The broncho -trachealis posticus is the hinder 

 fasciculus formed by the forking of the last-named 

 muscle. Its fibres pass downwards and backwards, and 

 are inserted into the end of the third half-ring of the 

 same side. 



32. The broncho-trachealis anticus is the remaining 

 limb of the bifurcation of the lower extremity of the 

 tracheo-lateralis. Its fibres descend downwards and 

 forwards to insert themselves upon the anterior extremity 

 of the third half-ring of the corresponding side (Fig. 19). 



33. The broncho-trachealis brevis is, upon either side, 

 a strong, straight, subcylindrical bundle of muscular fibres 

 which arise above just beneath the broncho-trachealis 

 anticus muscle, descend rather obliquely across the larynx, 

 to become inserted into the hinder end of the second 

 bronchial half-ring (Fig. 14, 6). This muscular slip, as is 

 shown in Fig. 19, is considerably larger than the broncho- 

 trachealis posticus, which passes down, for the major 

 part of its descent, alongside of it. 



34. The bronchialis posticus is a chunky little spindle - 

 formed muscle, situated below the other muscles just 

 described. It arises by its superior apex from the 

 latero-inferior margin of the ultimate tracheal ring, 



