﻿REVIEW 
  OF 
  THE 
  ATLANTIC 
  PERIWINKLES 
  — 
  ABBOTT 
  457 
  

  

  Figure 
  57. 
  — 
  Radulae 
  of, 
  a, 
  Echininus 
  nodulosus 
  Pfeiffer, 
  b, 
  Nodilittorina 
  tuberculata 
  Menke, 
  

   c. 
  Modulus 
  modulus 
  Linne, 
  and, 
  d, 
  the 
  central 
  tooth 
  of 
  Tectarius 
  muricatus 
  Linne. 
  (Arrows 
  

   point 
  to 
  side 
  views 
  of 
  teeth.) 
  

  

  