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JAMES ROLLIN SLONAKER 



When the origins of the muscles are dissected loose and they 

 are laid back (fig. 11) the quadratus (Q) and the pyi-amidalis 

 (P) with its tendon (7") are easily seen. The shape of the quad- 

 ratus resembles that of a thin section through a truncated pyi'a- 



Fig. 11 Enlarged drawing of the posterior view of the right eye of the spar- 

 row with the rectus superior (Rs), inferior {R inf), externus (Re), internus (Rin), 

 and the superior {Os) and inferior (Oi) oblique muscles laid back to show the 

 arrangement of the quadratus (Q) with its loop (L), and the pyramidalis (P) 

 with its tendon (T), in relation to the optic nerve (Op). 



mid. Its broad base is attached to the eyeball under the inser- 

 tion of the superior oblique and superior rectus muscles. From 

 this region it extends downwards and terminates abruptly in a 

 broad, tendinous loop just above the optic nerve. The pyra- 

 midalis muscle, as its name implies, is much the shape of a thin 



