614 



MOLLUSCOIDEA. 





more or less numerous Polyzoa (fig. 457); but the Upper Oligocene 

 of Germany, the Miocene deposits of France, Austria, Switzerland, 



Fig. 457. — Types of Tertiary Polyzoa. a, A few cells of Microporella violacea (Pliocene and 

 Recent), magnified ; b, Cellepora corouopus, of the natural size, and a portion of the surface en- 

 larged (Pliocene); c, A small piece of Cellaria (Salicornaria) crassa, of the natural size 

 and enlarged (Pliocene) ; d, Lnnulites quadrata, of the natural size, and a small portion of the 

 upper surface enlarged (Tertiary) ; E, A fragment of Sc?-upocellaria elliptica, viewed from 

 behind, enlarged (Tertiary); f, A small piece of Crisia denticirtata (Tertiary), enlarged; G, A 

 fragment of Tubulipora flabellaris (Tertiary), enlarged ; h, A fragment of Diastopora simplex, 

 enlarged (Tertiary); i, A piece of Vincularia Haidingeri, natural size and enlarged (Tertiary) ; 

 J, Idmoneafenestrata, natural size and enlarged (Tertiary) ; k, Hornera reteporacea, natural 

 size and enlarged (Tertiary). (After Busk and Reuss.) 



and Italy, and the Pliocene beds (" Coralline Crag ") of Britain, 

 have proved particularly rich in the remains of these organisms. 

 In the following general account of the characters and chief groups 



