152 Practical Zoology. 



7. Note the thin layer of cartilage over the ends of the 

 bones. Feel of it. Cut it. What are its properties, and what 

 its uses ? 



8. With the forceps strip off a little of the muscle sheath from 

 one of the muscles and note the color of the latter. Cut one of 

 the muscles across in its middle and examine the cross section. 

 Each fiber has its own thin sheath, and the small bundles of 

 fibers have separate sheaths, which make the white markings 

 seen in chipped dried beef. 



9. Tear off a few fine fibers of the muscle, mount on a slide 

 in water or glycerine, cover with a cover slip, and examine first 

 with a low and then with a high power. The fine cross- 

 markings of the fibers give to this kind of muscle the name of 

 striped, or striated, muscle. 



10. The covering of the bones is the periosteum. Thoroughly 

 clean one of the long bones and make a drawing of it. Saw it 

 in two lengthwise and make a drawing of the surface thus ex- 

 posed. Put a bone into weak acid, and after a day or two com- 

 pare it with another that has been burned. 



THE MUSCLES OF THE EYEBALL. 



With bone forceps, or a strong knife, cut away the bone at the 

 outer angle of the eye socket of the rabbit (almost any mammal 

 will serve for this, but the bone is so thick in the calf or sheep 

 that it will be difficult work without the aid of a good pair of bone 

 forceps) . 



1. With scissors trim away the white membrane around the 

 front of the white of the eye ; this was continuous with the lining 

 of the eyelid, and is the conjunctiva. 



2. Find a muscle running along the roof of the eye socket, 

 which passes over a loop of tendon, near the edge of the orbit, 

 and turns outward to its attachment to the top of the eyeball. 

 This is the superior oblique muscle. 



3. Beneath the eye find a muscle, having its origin in the 

 inner front part of the socket, and passing outward to be 



