﻿250 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Genus 
  alasmidonta 
  Say. 
  1818 
  

  

  The 
  shell 
  is 
  ovate, 
  solid 
  and 
  inflated, 
  shining, 
  with 
  strong 
  beak 
  

   sculpture. 
  Cardinal 
  teeth 
  thick 
  and 
  strong; 
  the 
  laterals 
  are 
  short, 
  

   sometimes 
  not 
  present. 
  

  

  Alasmidonta 
  calceola 
  (Lea) 
  Simpson 
  1900 
  (Fig. 
  186). 
  U 
  n 
  i 
  o 
  

   c 
  a 
  1 
  c 
  e 
  o 
  1 
  u 
  s 
  Lea 
  (1830. 
  Philos. 
  soc. 
  Trans. 
  3 
  126^). 
  A 
  1 
  a 
  s 
  - 
  

   ^^^^ 
  midonta 
  calceola 
  Simpson 
  (1900. 
  U. 
  S. 
  

  

  Y 
  ^-fe 
  . 
  fiat. 
  mils. 
  Proc. 
  22:668) 
  

  

  f 
  "V 
  ) 
  Shell 
  small, 
  solid 
  and 
  inflated; 
  surface 
  smooth; 
  

  

  L_ 
  ^ 
  anterior 
  end 
  rounded 
  ; 
  posterior 
  end 
  triangular 
  ; 
  

  

  Fig. 
  186 
  Alasmidonta 
  ^^^^al 
  margin 
  oval 
  ta 
  the 
  umbo, 
  whence 
  it 
  has 
  a 
  

   ^^^(^^oia, 
  deep 
  inward 
  curve, 
  back 
  of 
  and 
  under 
  the 
  beak; 
  

  

  ventral 
  margin 
  straight; 
  muscle 
  impressions 
  deep 
  and 
  well 
  defined; 
  

   pallial 
  line 
  clear; 
  beaks 
  prominent, 
  inflated, 
  more 
  or 
  less 
  sculptured. 
  

  

  Locality. 
  Goat 
  island. 
  

  

  Alasmidonta 
  truncata 
  (Wright) 
  Simpson 
  1900 
  (Fig. 
  187). 
  

   Margaritana 
  marginata 
  var. 
  truncata 
  Wright 
  

   (1898. 
  Nautilus, 
  1 
  1 
  :i24). 
  Alasmidonta 
  truncata 
  Simp- 
  

   son 
  (1900. 
  U. 
  S. 
  nat. 
  mus. 
  Proc. 
  22:671) 
  

  

  Shell 
  elongated, 
  quadrangular 
  and 
  heavy; 
  surface 
  marked 
  by 
  dis- 
  

   tinct 
  growth 
  Hnes, 
  which 
  are 
  crossed 
  by 
  transverse 
  wrinkles 
  on 
  the 
  

   posterior 
  slope 
  ; 
  posterior 
  end 
  angulated 
  ; 
  anterior 
  end 
  rounded 
  ; 
  dor- 
  

  

  Fig. 
  187 
  Alasmidonta 
  truncata 
  

  

  sal 
  margin 
  curved 
  outward 
  at 
  the 
  umbo; 
  ventral 
  margin 
  straight 
  or 
  

   nearly 
  so; 
  muscular 
  impressions 
  deep, 
  particularly 
  the 
  anterior 
  ad- 
  

   ductor; 
  pallial 
  line 
  distinct; 
  beaks 
  large, 
  prominent 
  and 
  incurved, 
  

  

  