﻿1022 
  Forty- 
  seventh 
  Report 
  on 
  the 
  State 
  Museum, 
  

  

  coalesced 
  with 
  the 
  lateral 
  walls 
  of 
  the 
  pedicle-valve 
  and 
  the 
  

   teeth 
  upon 
  the 
  margins 
  of 
  that 
  valve. 
  Hinge-plate 
  small, 
  divided 
  

   by 
  a 
  shallow 
  incision. 
  Cardinal 
  process 
  absent. 
  

  

  Type, 
  Wilsonia 
  Wilsoni, 
  Sowerby 
  (sp.). 
  

  

  Distribution. 
  Upper 
  Silurian 
  — 
  Lower 
  Devonian. 
  

  

  Uncinulus, 
  Bayle. 
  1878. 
  

   (Plate 
  44, 
  figs. 
  6-9.) 
  

   Synonym; 
  Unoinulina, 
  Bayle, 
  1878. 
  

   Shells 
  exteriorly 
  like 
  "Wilsonia 
  ; 
  interiorly 
  with 
  a 
  solid, 
  undi- 
  

   vided 
  hinge-plate 
  and 
  a 
  highly 
  developed 
  cardinal 
  process. 
  

   Type, 
  Uncinulus 
  subwilsoni, 
  d'Orbigny 
  (sp.). 
  

   Distribution. 
  Devonian. 
  

  

  Hypothyris, 
  (McCoy) 
  King. 
  1850. 
  

   (Plate 
  44, 
  figs. 
  10-13.) 
  

  

  Shells 
  strongly 
  subcuboidal. 
  Teeth 
  usually 
  supported 
  by 
  short 
  

   vertical 
  lamellse; 
  hinge- 
  plate 
  quite 
  small 
  and 
  composed 
  of 
  two 
  

   broad, 
  short 
  lateral 
  processes, 
  which 
  are 
  divided, 
  for 
  a 
  portion 
  of 
  

   their 
  length 
  only, 
  by 
  a 
  median 
  incision 
  extending 
  to 
  the 
  bottom 
  of 
  

   the 
  valve 
  but 
  not 
  forming 
  an 
  inceptive 
  spondylium 
  as 
  in 
  Camaro- 
  

   tgechia. 
  Dental 
  plates 
  large. 
  There 
  is 
  but 
  the 
  barest 
  indication 
  

   of 
  a 
  median 
  septum 
  in 
  the 
  brachial 
  valve. 
  Muscular 
  impressions 
  

   small 
  and 
  not 
  deep 
  ; 
  those 
  of 
  the 
  pedicle- 
  valve 
  making 
  an 
  oval 
  

   scar 
  continued 
  from 
  the 
  narrow 
  pedicle-cavity 
  ; 
  those 
  of 
  the 
  

   brachial 
  valve 
  being 
  narrow, 
  elongate 
  and 
  extremely 
  obscure. 
  

   Interior 
  of 
  the 
  pedicle-valve 
  frequently 
  preserving 
  the 
  ovarian 
  

   pittings 
  and 
  vascular 
  sinuses 
  while 
  the 
  characters 
  are 
  but 
  faintly 
  

   retained 
  on 
  the 
  brachial 
  valve. 
  

  

  Type, 
  Hypothyris 
  cuboides, 
  Sowerby 
  (sp.). 
  

  

  Distribution. 
  Devonian. 
  

  

  Subgenus 
  Pugnax, 
  Hall. 
  1893. 
  

   (Plate 
  44, 
  figs. 
  14-25.) 
  

  

  Shells 
  with 
  deep 
  fold 
  and 
  sinus 
  ; 
  elevated, 
  and 
  often 
  acuminate 
  

   on 
  the 
  anterior 
  margin 
  ; 
  more 
  or 
  less 
  sharply 
  plicated, 
  the 
  

   plications 
  usually 
  being 
  simple, 
  those 
  of 
  the 
  fold 
  and 
  sinus 
  the 
  

   strongest, 
  and 
  those 
  of 
  the 
  lateral 
  slopes 
  often 
  obscure 
  or 
  

   obsolete. 
  Pedicle-valve 
  shallow; 
  brachial 
  valve 
  deep. 
  Teeth 
  

   supported 
  by 
  vertical 
  lamella 
  ; 
  hinge-plate 
  similar 
  in 
  structure 
  

  

  80 
  

  

  