BY W. J. McKAY. 985 



Fig. 20. — The intermandibularis (I.M.) is shown giving oS{IM'.) a slip to 

 the integument {CM.); the cerato-mandibularis joins the inter- 

 mandibularis in front. (/.iy.(T.) inferior labial gland. 



Fig. 21. — The costo-mandibular {C.G.M.) is seen running forward to join the 

 depressor mandibul^ (D.M.) to form the mylohyoid {M.H.). 

 On the left side of the figure the mylohyoid has been removed, 

 and we see the masseter {M.), posterior temporal {P.T.), and 

 internal pterygoid {I. P.). The external intercostals are seen, and 

 the scalene muscles, while the rectus capitis anticus {B.C. A.) lies 

 still more deeply. 



Fig. 22. — The lower jaw has been removed. On the left side we have the 

 internal pterygoid reflected, and the parieto-pterygoid and spheno- 

 pterygoid displayed. On the right side of the figure we have the 

 internal pterygoid, and the aponeurosis of the roof of the mouth 

 (P. A .). Anteriorly we see the small spheno-vomerine muscle 

 {S.V.). 



Fig. 23. — The muscles composing the greater portion of the erector spinse. 

 The spinalis dorsi is seen to lie next the spinous processes (S.) and 

 to break up into tendons which run forward to be inserted in the 

 spines {S.J . The tendons of these muscles are intimately connected 

 and form a distinct aponeurosis. {L.D.) the longissimus dorsi 

 group ; the superior layer is seen to give off tendons which run out- 

 wards and form the tendons of origin of the sacro-lumbalis group. 

 The inferior tendons run inwards and join with the tendons of the 

 spinalis dorsi group. 



Fig. 24. — (S.L.) the sacro-lumbalis column, arising in part from the longissi- 

 mus dorsi column, and inserted along with the tendons of the 

 pretrahentes costarum superiores (P.C.S.). Between the tendons 

 of the latter muscles are the tendons of the external oblique {Ex.O,)> 



Fig. 25. — The muscles on the lateral aspect of the snake's body. The 

 tendons of the sacro-lumbalis [S.L.) are seen to be inserted 

 into the ribs along with the tendons of the pretrahentes 

 costarum superiores {P.C.S.). The external oblique {Ex.0.) is seen 

 to be composed of bundles intimately connected with the rectus 

 {P.M.). The internal oblique springs from the costal cartilages as 

 'Heaves "of muscles, and running forward these are attached to 

 the spaces between the scutal muscles {S.M.). A tendinous band 

 (I.O.T.) continues the muscle towards the midline where it joins 

 the tendon of the trans versalis {T.T.). The fibres {Ex. I'.) are 

 modified external intercostal muscles. 



