PLATE 9 
Anterior surface of left humerus; about one-half natural size. 
Fig. 38. No. 8987, Castor subauratus. 
Fig. 39. No. 12654, Castor subauratus. 
Fig. 40. No. 12668, Castor subauratus. 
Fig. 41. No. 16385, Castor subauratus. 
Fig. 42. No. 19229, Castor fiber. 
Fig. 48. No. 210, Castor canadensis phaeus. 
Fig. 44. No. 4347, Castor canadensis belugae. 
Fig. 45. No. 12101, Castor canadensis leucodonta. 
Note that the bicipital groove is deeper and larger in canadensis and fiber 
than in subauratus. The proximal origin of the deltoid ridge is more distally 
located in canadensis than in subauratus or fiber; the longitudinal measurement 
of the internal condyle is greater in fiber and canadensis; the supinator ridge 
forms an even curve in fiber and subauratus, but an angle in canadensis. 
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