I.] DISSECTION OF A RABBIT AND OF A DOG. 11 



B. 1. Make a median incision over the skull from the 

 nose to behind the Ifevel of the ears. Reflect the 

 skin on each side. Cut away the attachment of 

 the muscles of the neck to the occiput until the 

 occipito-atlantoidean membrane between the 

 occiput and the atlas is laid bare. Carefully 

 divide this with scissors and observe the medulla 

 oblongata. 



2. With a trephine saw through the roof of the 

 skull in its broadest part, a little behind the 

 orbits, working very carefully when the bone is 

 nearly sawn through. With a lever raise the 

 circular piece of bone and remove it. Then 

 with the bone forceps cut away piecemeal the 

 rest of the roof of the skull. 



8, Note the thickish membrane, the dura mater 

 covering but not attached to the brain, it dips 

 down between the cerebral hemispheres as the 

 falx cerebri and between the cerebrum and 

 cerebellum as the tentorium; cut away the dura 

 mater and observe the very thin vascular mem- 

 brane, the pia mater, clinging to the surface of 

 the brain, 



4. Make a rough sketch of the exposed cerebrum, 

 cerebellum and medulla oblongata for com- 

 parison with the same parts in the dog. Note 

 particularly that in the rabbit the cerebral 

 hemispheres are smooth and that the olfactory 

 lobes are directly in front of the cerebral 

 •hemispheres, being separated from them by a 

 constriction only.- - 



