1885.] 



MYOLOGY OF THE WATER-OPOSSUM. 



19 



Fig. 6. 



ajs 



FMnD. 



Sm. 

 FXJ). 



J'.L.F. 



Myology of Water-Opossum. 



Q,.E., quadriceps extensor; T.A., tibialis anticus; E.L.D., extensor longus digi- 

 torum ; £'.X.P., exteusor longus pollicis ; P.L., peroneus longus; P.B., 

 peroneus brevis ; P. T.D., peroneus tertii digiti ; P.Qr.D., peroneus quarti 

 digiti ; G.E., gastrocnemius externus ; PI., plantaris ; T.P., tibialis 

 posticus ; F.L.P., flexor longus polliois ; 8m., semimembranosus ; Pop., 

 popliteus ; i'^.i.Z'., flexor longus digitorum ; (r., gracilis ; iSY., semiten- 

 dinosus. 



Muscles of Head and Neck. 



Masseter. — Enormously developed. Can be easily separated into 

 Sfveral strata. The most superficial fibres arise from the strong 

 masseteric fascia, and, passing inwards and backwards, are inserted 

 into incurved portion of lower jaw. 



The next fibres, which also pass backwards, arise from lower 

 border of zygoma, and are inserted into a ridge, extending from 

 condyle of lower jaw along lower border of outer surface. The most 

 internal part arises from lower border and inner surface of zygoma, 

 and its fibres, passing downwards and slightly forwards for the 

 most part (the most anterior fibres passing slightly backwards), are 

 inserted into outer surface of ramus between oblique line and dental 

 foramen. The most posterior fibres of the superficial portion of the 

 muscle are inserted into a tendinous raphe behind the ramus, which 

 receives the most posterior fibres of internal pterygoid on its inner 

 surface. 



Temporal.— Consists, of two easily separable laminae. Superficial 

 portion, thin in its posterior two thirds, arises from posterior 

 part of inner surface of zygoma inseparable from masseter, and 

 from a small portion of upper border of zygoma at its posterior 



2* 



