EXTINCT ANIMALS 



in the Lower Cambrian rocks (see Table of Strata, 

 p. 60), and are the remains of small marine 

 creatures, which were, however, by no means 

 very simple in structure. One of these is the 

 Lingula davisii (Fig. 199), from the Lingula 



Fig. 198. — Loligo media, a cuttle-fish or squid now living in 

 British seas. On the left is seen the long horny " pen," 

 which, like the Belemnite, is embedded in the animal's 

 back. (Lent by jbhe Trustees of the British Museum. ) 



flags of Wales. Only the simple oval shells are 

 known, but they are almost exactly like the 

 shells of a marine animal which is still found 

 living in immense numbers on the shores of the 

 warmer oceans. The Hving owners of these shells 

 occur in great numbers burrowing in sand and 



272 



