﻿Report 
  of 
  the 
  State 
  Geologist. 
  

  

  1089 
  

  

  dium 
  reduced 
  to 
  two 
  lateral 
  expanded 
  processes 
  arising 
  from 
  the 
  

   elevated 
  anterior 
  portion 
  of 
  the 
  septum 
  and 
  representing 
  the 
  

   ascending 
  process. 
  

  

  Figs. 
  627-630. 
  Kraussina 
  rubra, 
  Pallas 
  (sp.). 
  (Davidson.) 
  

  

  Type, 
  Kraussina 
  rubra, 
  Pallas 
  (sp.). 
  

  

  Distribution. 
  Eecent 
  (South 
  African 
  and 
  Australo-Zealandian 
  

   Provinces). 
  

  

  Mannia, 
  Dewalque. 
  1874. 
  

  

  Small 
  magadiform 
  shells, 
  with 
  the 
  brachidium 
  consisting 
  of 
  

   two 
  descending 
  processes, 
  not 
  uniting 
  with 
  the 
  median 
  septum, 
  

   the 
  latter 
  bearing 
  at 
  its 
  extremity 
  two 
  disunited 
  lamellae 
  which 
  

   represent 
  the 
  ascending 
  branches. 
  

  

  Type, 
  Mannia 
  Nysti, 
  Dewalque. 
  

  

  Distribution. 
  Miocene. 
  

  

  Platidia, 
  Costa. 
  1852. 
  

  

  Shells 
  small, 
  biconvex, 
  smooth, 
  with 
  large 
  punctures. 
  Foramen 
  

   large, 
  encroaching 
  on 
  both 
  valves 
  ; 
  no 
  deltidial 
  plates. 
  Teeth 
  

   and 
  sockets 
  small. 
  In 
  the 
  brachial 
  valve 
  the 
  median 
  septum 
  

   is 
  reduced 
  to 
  a 
  vertical 
  plate 
  which 
  rises 
  near 
  the 
  center 
  of 
  the 
  

  

  Figs. 
  631-633. 
  Platida 
  anomioides, 
  ScaccbJ. 
  (Davidson.) 
  

  

  valve. 
  To 
  this 
  plate 
  the 
  descending 
  branches 
  of 
  the 
  loop 
  are 
  

   united; 
  ascending 
  branches 
  not 
  represented; 
  brachia 
  in 
  three 
  

   lobes, 
  the 
  median 
  lobe 
  surrounding 
  the 
  oral 
  orifice 
  and 
  not 
  

   spirally 
  coiled. 
  

  

  137 
  147 
  

  

  