A MANUAL OF ZOOLOGY 79 



generative systems. Dissect away the lower jaw by break- 

 ing it down and cutting carefully. Note the ball and 

 socket articulation and the openings into the larynx and 

 the oesophagus. How does the tongue compare with the 

 tongue in the other forms? Pass a bristle into the nostril 

 and notice where it enters the mouth. Note the median 

 fissure in the roof of the mouth and the little papillae 

 fringing its edge. Which way do they slant? What is 

 their use? Dissect out the ear noting the outer ear drum 

 composed of an inpocketing of the skin. Back of this find 

 the middle ear. Pass a bristle into the lower opening 

 leading inwdrd from this and find where it leads. By care- 

 fully breaking away- the bone find the inner ear with" its 

 semicircular canal. Remove the upper mandible by bend- 

 ing it upward and breaking it off. Dissect out the eye, 

 noting the four recti, and the two oblique muscles attached 

 to its surface.' Note the cartilaginous ring surrounding 

 the cornea. Compare this with the turtle. Open the cor- , 

 nea and note in order the aqueous humor, the iris, the 

 crystaline lens, the vitreous humor, the retina, the choroid, 

 and the sclerotica. Make a sketch of the front and also 

 one of the side view of the lens. Which side is more 

 convex? Compare its shape with that of each form 

 studied. Dissect out the brain by picking away the thin 

 bone covering it. Note the small conical olfactory lobes, 

 the cerebral hemispheres, the pineal body, the transversely 

 grooved cerebellum, the round optic lobes, the medulla, the 

 infundibulum, and the optic chiasma. Note especially the 

 very large cerebrum. Compare this brain in every point 

 here named with that of the forms studied before. Make 

 a sketch of the upper and one of the under surface of the 

 brain. Dissect away and scrape clean the wing and at- 

 ,tached scapula. Make a drawing and name on it the fol- 

 lowing-parts: scapula, humerus, radius and ulna, carpal 

 bones, carpo-metacarpus, and phalanges. Dissect away and 

 scrape clean the bones of the leg. Make a drawing of this 

 and name the parts; femur, tibia, fibula, tarso-metatarsus, 

 and the phalanges. How do the tibia and the fibula 

 compare with those in the forms studied before? Dissect 

 out some cervical vertebrae and not.e the method of articu- 

 lation. 



