320 MR. T. ATTHET OX AXTHItACOSATTETIS RTJSSELLI. 



posterior end the bone is fractured longitudinally for two inches 

 and three-quarters. At three-quarters of an inch from its upper 

 border, the lower half inch is pressed up above the upper. The 

 two halves, when united, are one inch and a quarter in depth. 

 The bone at this fracture measures three-tenths of an inch in 

 breadth. For two inches in front of the fracture the presphenoid 

 is perfect, and is one inch in depth ; and from this point to the 

 anterior end it rapidly diminishes to one-tenth of an inch in 

 depth, as above stated. 



The supratemporal or pterygoid arches, as seen from below, are 

 two inches and a half in length, by about three inches in width, 

 bounded anteriorly and internally by the pterygoids, externally 

 by the quadrate- jugal, and posteriorly by the quadrates. 



The basisphenoid is united in front to the posterior margin of 

 the median ridge or presphenoid, and behind by a transverse 

 suture, to the apex of the basioccipital. Its outer borders are 

 difficult of definition, owing to the crushed state of the bones. 



At three-tenths of an inch behind the anterior margin of the 

 bone there is an oblique projection on each side of the middle 

 line ; these are half an inch apart at their anterior, and one 

 inch and two-tenths at their posterior ends ; and each is six- 

 tenths of an inch long. A well-defined smooth and deep groove 

 or channel runs along the inner sides of their bases from before 

 backwards. 



The basioccipital is two inches and a half long by one inch and 

 three-quarters broad at its posterior pait, and half an inch at its 

 apex. It is articulated in front to the basisphenoid, and on each 

 side apparently to the quadrate bone. The deep cavity behind 

 for articulation to the body of the first cervical vertebra is bro- 

 ken off obliquely near to its posterior margin ; and the anterior 

 part which remains is much compressed. 



The occipital surface is one inch and one-tenth in depth from 

 the posterior borders of the so-called supraoccipitals or top of the 

 skull to the lower border of the basioccipital. On the left side 

 of the median suture the bones are entire to near the outer 

 margin or angle of the exoccipital ; on the right side part of the 

 exoccipital is broken obliquely off, together with a part of the 



