Osteological Symmetry of the Catnel. 531 



The Tail. 



The dimensions of the bones of the tail, relatively to the other 

 bones of the body, are perhaps more curious than interesting. 



The sum of their lengths is equal to the greatest spinal extent 

 in the dorsal vertebrae, namely, to that of the 3rd dorsal ver- 

 tebra. 



The sum of their transverse breadths is equal to the greatest 

 transverse extent in the lumbar vertebrae, namely, to that of the 

 5th lumbar vertebra. 



The sum of the breadths at their oblique processes equals the 

 sum of their spinous heights : and both are equal to the greatest 

 transverse aperture of the pelvis. 



The sum of their rostral thicknesses is twice the caudal height 

 of the head : and the tip of the tail may be compared with the 

 aperture of the auditory canal. 



Of the Ribs. 



The longest of the twelve ribs are the 7th and the 8th. The 

 length of each of these equals the length of the spine of the sca- 

 pula, being the greatest extent of that bone. 



The decrements of length in the other ribs, rostrad from the 

 7th, and caudad from the 8th, are such, that 



The 6th rib corresponds with the 10th, 



The 5th with the 11th, 



The 4th with the 12th. 



The sum of the lengths of the twelve ribs is about ten times that 

 of the longest rib. 



'&^ 



At the sternal end of the ribs the breadth is greatest. The 

 broadest are the 4th and the 5th ; their breadth equals that of 

 the cranium at the temporal fossae. 



The sum of the breadths of the ribs at their sternal ends is 



eight 



