﻿1088 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum, 
  

  

  turn 
  ; 
  above 
  their 
  insertion 
  arise 
  the 
  ascending 
  processes 
  which 
  

   are 
  broad, 
  concave, 
  triangular 
  plates, 
  with 
  their 
  apices 
  tapering 
  

   backward 
  but 
  not 
  uniting. 
  

  

  Figs. 
  623-626. 
  Magas 
  pumilus, 
  So 
  werby. 
  (Davidson.) 
  

  

  Type, 
  Magas 
  pumilus, 
  So 
  werby. 
  

   Distribution. 
  Cretaceous. 
  

  

  Rhynchora, 
  Dalman. 
  1828. 
  

  

  Shell 
  elongate-ovate, 
  coarsely 
  plicate. 
  Hinge-line 
  short, 
  

   straight. 
  Foramen 
  large, 
  subcircular, 
  deltidial 
  plates 
  wanting. 
  

   Teeth, 
  sockets 
  and 
  cardinal 
  process 
  well 
  developed. 
  A 
  low 
  

   median 
  septum 
  in 
  each 
  valve. 
  Loop 
  not 
  known. 
  

  

  Type, 
  Rhynchora 
  costata, 
  Wahlenberg 
  (sp.). 
  

  

  Distribution. 
  Cretaceous. 
  

  

  Rhynchorina, 
  (Ehlert. 
  1887. 
  

  

  Shells 
  small, 
  transverse, 
  the 
  hinge 
  line, 
  which 
  is 
  straight, 
  mak- 
  

   ing 
  the 
  greatest 
  diameter 
  of 
  the 
  valves. 
  Umbones 
  very 
  depressed. 
  

   Surface 
  smooth. 
  Teeth 
  and 
  sockets 
  placed 
  at 
  the 
  cardinal 
  extrem- 
  

   ities. 
  Brachial 
  valve 
  with 
  a 
  broad 
  cardinal 
  plate 
  or 
  area 
  extend- 
  

   ing 
  for 
  the 
  entire 
  length 
  of 
  the 
  hinge 
  ; 
  at 
  its 
  center 
  is 
  a 
  callosity 
  

   or 
  cardinal 
  process, 
  which 
  is 
  supported 
  by 
  a 
  median 
  septum. 
  

   Loop 
  like 
  that 
  of 
  Magas. 
  

  

  Type, 
  Rhynchorina 
  spathulata, 
  Wahlenberg 
  (sp.). 
  

  

  Distribution. 
  Cretaceous. 
  

  

  Kraussina, 
  Davidson. 
  1859. 
  

  

  Synonym 
  ; 
  Kraussia, 
  Davidson, 
  1852. 
  

  

  Shells 
  biconvex, 
  plicate, 
  subcircular 
  or 
  oval 
  ; 
  hinge-line 
  straight; 
  

   foramen 
  large, 
  deltidial 
  plates 
  incomplete. 
  Interior 
  of 
  the 
  bra- 
  

   chial 
  valve 
  with 
  cardinal 
  process 
  and 
  median 
  septum. 
  Brachi- 
  

  

  146 
  

  

  