222 



VEBTEBKATE ANIMALS. 



A •„ /i5=+iT>D-uisted by the following characters : The skull 

 ^ud lowef^aw are wen developed, but the skull is not com- 



rio. 108.— CepAotospis ZyeBit, from the Old Bed Sandstone of Scotland, 



posed of distinct bones, and simply forms a kind of cartila- 

 ginous box. The vertebral column is sometimes cartilaginous, 

 sometimes composed of distinct vertebrae. The integument- 

 ary skeleton is in the form of placoid scales (Fig. 100, c) — 



""■"-'""'"— ^- ^^«si.r-->■ B.K..O. 



the Herrings 



