12 PROCEEDINGS OF THE NATIONAL. MUSEUM tol. 6T 



It is clear that the original injury was received by the animal 

 when the bones were extremely plastic. It is equally apparent that 

 the injury was in the nature of a smart blow upon the side of the 

 head, such as might have been received by a fall from a ledge upon 

 a sharp rock some distance below. 



The occipital bone is entirely sjonmetrical, but this, perhaps with 

 the pterygoids, is the only portion of the skull of which this may be 

 said. 



Beginning at the point of original injury, it is seen that the jugal 

 has been fractured in at least one and possibly two places. This, 

 however, as well as the distal end of the zygomatic process of the 

 squamosal, is now so distorted that but little can be told from it. 

 That the injury took place during the very early life of the animal 

 can be seen not alone by the general distortion, but from the fact 

 that the left zygomatic arch is very much stunted; not that it is short- 

 ened, of course, but that it has failed to grow at anywhere near the 

 normal rate. An examination of the glenoid fossa upon this side dis- 

 closes the fact that the medial portion of its concavity is granular 

 and distorted in form. There was assuredly further injury at this 

 point, and some sort of fracture or derangement of the precise rela- 

 tionship between the bones immediately caudad, so that they failed 

 to grow at the normal rate. This certainly seems to be the sole ex- 

 tent to which the skull was directly injured, all other details of asym- 

 metry having been due to indirect influences. 



An early and complete fusion of the adjacent sutures evidently 

 followed the injury to the last-mentioned region, which resulted in a 

 permanent stunting of this portion of the skull. The left auditory 

 and petrous part of the temporal are especially affected, being small 

 and misshapen. The resistance to growth may have been augmented 

 by the pressure of the left mandibular ramus against its glenoid 

 fossa, caused by increasing displacement of the rostrum, although 

 this was not the primary factor in causing the condition. The dis- 

 tance between the left zygomatic process of the squamosal and the 

 normal mastoid is but 4.5 mm., while the same distance upon the 

 right side measures 18 mm. As the mastoids, occipital, and lamb- 

 doidal crests are entirely normal, or at least symmetrical, it is seen 

 that there is a sharp bending of the cross axis of the skull, tlxrough 

 the glenoid fossae, of four degrees. This, carried at right angles to 

 the anteriormost point of the mandibular symphysis, would show a 

 lateral deflection from the normal axis of the skull (as projected at 

 right angles to the occipital plane) of about 20 mm., even were there 

 no other asymmetrical forces operative. As a matter of fact, other 

 conditions have contributed to increase this deflection so that it 

 actually approximates 65 mm., as near as can be calculated. 



