OF DENISON UNIVERSITY. 



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fact, the sternum is a valuable osteological index, for, not only is it 

 pretty constant in a given family, but it presents points of constant 

 difference between many families. The manubrium is larger, if any- 

 thing, than in the Grosbeak. 



Such are some of the differences noted between these species and 

 they may be taken as indications of those points in the osseous struc- 

 ture most readily responding to changes in habit or habitation as in- 

 duced by changes in the environment. It is by the elimination of 

 the variable elements of different degrees of constancy that classifica- 

 tion can be placed upon a permanent and correct basis. The vari- 

 able points may be employed in distinguishing species, genera, etc., in 

 accordance with their relative permanence or value. 



Plate I. Anatomy of Hesperiphona. 



Fig. 1. Lateral view of entire skeleton. 



Fig. 2. Skull seen from below. Qj, quadratojugal ; PI, palatal ; pt, ptery- 

 goid ; sp, sphenoid ; e, condyle ; Fiii, foramen magnum ; Z, internal flange of 

 mandible. 



Fig. 3. Transverse section of skull F, vomer ; Q, quadrate bone ; Of, 

 optic foramen ; other references as above. 3^, diagram of bones of skull. 



Fig. 4. Quadrate bone and articulations Pi, pterygoid ; Qj, quadratoju- 

 gal ; a, accessory ossicles ; ui c, sheath of Meckel's cartilage. 



Fig. 5. Hyoid arch. 



Fig. 6. Superior surface of a cervical vertebra. 



Fig. 7. Humerus. 



Fig. 8. A dorsal vertebra, from behind. 



Fig. 9 Muscles of the wing seen from above. 



Fig. qA. ATiterior part of wing from below. 



Fig. 10. Skull denuded of skin and showing certain cervical muscles. 



