﻿1052 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  Type, 
  Notothyris 
  subvescicularis, 
  Davidson 
  (sp.) 
  . 
  

   Distribution. 
  Devonian 
  ? 
  — 
  Carboniferous. 
  

  

  Fig. 
  474. 
  

  

  Fig. 
  476. 
  

  

  Fig. 
  ^75. 
  

  

  Notothyris 
  subvescicular 
  is, 
  Davidson. 
  

   Fig. 
  474. 
  A 
  dorsal 
  view 
  of 
  the 
  exterior. 
  

   Fig. 
  475. 
  A 
  profile 
  of 
  the 
  same 
  shell. 
  

  

  Fig. 
  476. 
  The 
  interior 
  of 
  the 
  brachial 
  valve; 
  showing 
  the 
  perforated 
  hinge-plate 
  and 
  the 
  

   lateral 
  lamellae 
  of 
  the 
  loop. 
  (Waagen.) 
  

  

  Juvavella, 
  Bittner. 
  1890. 
  

   Shells 
  smooth, 
  biconvex, 
  with 
  a 
  low 
  median 
  sinus 
  on 
  the 
  pedicle- 
  

   valve. 
  Brachial 
  valve 
  with 
  a 
  very 
  short 
  loop, 
  the 
  descending 
  

   branches 
  uniting 
  to 
  form 
  an 
  expanded 
  vertical 
  median 
  plate. 
  

  

  Figs. 
  477, 
  478. 
  Juvavella 
  Suessi, 
  Bittner. 
  (Bittner.) 
  

  

  Type, 
  Juvavella 
  Suessi, 
  Bittner. 
  

   Distribution. 
  Trias. 
  

  

  Nucleatula, 
  Bittner. 
  1890. 
  

   Shells 
  having 
  the 
  general 
  external 
  aspect 
  of 
  those 
  of 
  Juvavella 
  

   but 
  with 
  a 
  larger 
  loop 
  in 
  which 
  the 
  vertical 
  median 
  plate 
  is 
  

   highly 
  developed 
  and 
  fimbriated 
  on 
  its 
  anterior 
  margins. 
  

  

  j./v 
  

  

  Figs. 
  479-484. 
  Nucleatuli 
  retrocit 
  a, 
  Suess 
  (sp.) 
  (Bittner.) 
  

  

  Type, 
  Nucleatula 
  retrocita, 
  Suess 
  (sp.). 
  

  

  Distribution. 
  Trias. 
  

  

  110 
  

  

  