320 THE HOUSE AND HIS STKTJOTURE. 



Instead of being a simple horny box, it is formed of thin 

 horny plates, called the horny laminae, set on their edges 

 side by side, very much like the leaves of a closed fan. 

 The number of these laminae is about six or seven hun- 

 dred if counted only upon the crust, but as they return 

 over the interior of the frog their number would be 

 doubled. I mention seven hundred on the authority 

 of several of our best veterinary surgeons, but in all the 



FRONT OF HOOF : TRANSVERSE SECTION. 



specimens that I have examined I have found that six 

 hundred is the average. 



Between the bone E and the horn is a layer of vascu- 

 lar and sensitive structure, i.e. which is traversed by 

 arteries, veins, and nerves. The blood-vessels are rather 

 large near the bone, but become smaller near the horn, 

 where they are formed into vascular laminae dipping 

 between the laminae of the horn, and so firmly attached 



