LESSON 27.] 



HAIR. 



91 



Hair of Seal. 



Mouse Hair. 



black and white cells FlG - 153 - Fl - 154 - FIG. 165. 



alternate, occupying 

 the whole diameter ; 

 in other portions the 

 black is broken up 

 into smaller rounded 

 bodies, and mixed 

 with the white. Nei- 

 ther is this all; the 

 hair enlarges gradu- 

 ally from the bulb, 

 then diminishes, and 



continues to do this four times before it ends in a point. 

 Each enlargement, too, is always larger than that which 

 preceded it, and the last the largest of all. 



A pretty little Marsupial animal (having a bag, or 

 pouch, like the Opossum), from Australia, Phascogale 

 penicillata, has hair somewhat resembling that of the 

 Mouse, inasmuch as each hair consists of four enlargements 

 (from the bulb), and corresponding diminutions. These Phascogale.' 

 hairs are of such great length, that it is out of the question to figure 

 an entire one, especially as the principal has been demonstrated in 

 the hair of Ornithorhyncus (Fig. 146). 



But enlarged detached portions are illustrated : thus, a figure of 

 the bulb, and commencement of the shaft (Fig. 155), is ^given. To 



Fin. 156. 



FIG. 157. 



FIG. 153. 



Succeeding portion, 

 le. 



Terminal enlarsred portion, 

 Phascogale. 



Hair of Indian 

 Bat: 



this succeeds a well imbricated structure (Fig. 156), the interior of 

 which displays medullary cells. 



The latter structure now prevails throughout the remainder of 



