37* 



ELEMENTARY ZOOLOGY 



' ' Practical Zoology. ' ' Make a good preparation of the 

 brain and preserve it for future use in some fluid like 

 Fischer's fluid (see page 453). 



TECHNICAL NOTE. Prepare a well-cleaned skeleton by boiling a 

 specimen in a soap solution and thoroughly cleansing it (seep. 452). 



Note the very compact skeleton of the mouse. Note 

 the closely sutured skull. How many cervical or neck 

 vertebrce are there ? The ribs are attached to the thoracic 

 vertebra. How many pairs of ribs ? The bony thorax 

 supports the shoulder-girdle and bones of the fore legs. 

 The thorax is followed by a series of ribless vertebrae, the 

 lumbar vertebrce, which in the posterior region of the body 

 fuse with the pelvic girdle supporting the hind limbs. 

 The body vertebrae are succeeded by the very much 

 smaller caudal vertebrce. Compare the skeleton of the 

 mouse with that of the bird; also with that of the toad. 

 For directions for a detailed study of the skeleton see in 

 Parker's " Zootomy " an ac- 

 count of the skeleton of the 

 rabbit, pp. 263-286. 



TECHNICAL NOTE. For the 

 study of the eye (fig. 150) the 

 teacher should obtain the eye of 

 some large mammal, as the ox or 

 sheep, with which to make a class 

 demonstration. The eye of a 

 rabbit or cat can of course be 

 used. For an account of the verte- 

 brate eye see Parker and Haswell's 

 " Text-book of Zoology, " Vol. II. 

 pp. 103-107. For a study of the 

 ear use a bird or mammal, and 

 see pp. 107-110 of the same book. F IG . 150. Diagram of vertebrate 



eye; c, choroid; z, iris; /, lens; n, 

 optic nerve; r, retina; s, sclerotic. 

 (From Kingsley.) 



Life-history and habits. 



The house-mouse is not a 



native of North America, but was introduced into this 



country from Europe, to which, in turn, it came from Asia, 



