So 



TWO YOUNG NATURALISTS. 



circumstances. Each of these channels terminates at its 

 base in a sort of conical cavity, filled by a whitish sub- 



HEAD OF THE WEEVER. 



o. Sheath of the spine. E, Spine, c, Follicle with gland. 



SECTION THKOTTGH THE MIDDLE OF THE SPINE. 



v, Blood- vessels, p, Skin and connective tissue, o, Prolongation of gland. 



SECTION OF SPINE AT THE BASE. 



P, Skin. E, Cartilage, c, Gland-cells, or, Granular part, o, Gland with 

 epithelial contents and connective envelope, in the cartilage. 



stance a sort of gland formed by cells. Some of these 

 are very large, and some have the appearance of having 



