﻿C. 
  D. 
  Walcott 
  — 
  Genus 
  Lingulepis. 
  405 
  

  

  In 
  a 
  review 
  of 
  the 
  Cambrian 
  Brachiopoda, 
  now 
  being 
  pre- 
  

   pared, 
  the 
  Cambrian 
  species 
  referred 
  to 
  the 
  genus 
  Lingu- 
  

   lepis 
  will 
  be 
  fully 
  illustrated. 
  

  

  Lingulepis 
  meeki, 
  n. 
  sp. 
  

  

  Shell 
  small 
  attenuate, 
  marked 
  by 
  rather 
  strong 
  concentric 
  

   lines 
  and 
  stride 
  of 
  growth, 
  and 
  interrupted 
  irregular 
  radiating 
  

   striae. 
  

  

  Yentral 
  valve 
  narrow, 
  elongate 
  ; 
  beak 
  acuminate, 
  rostral 
  

   slopes 
  long, 
  nearly 
  straight, 
  passing 
  gradually 
  into 
  the 
  curvature 
  

   of 
  the 
  anterolateral 
  margins, 
  and 
  posteriorly 
  meeting 
  at 
  a 
  very 
  

   acute 
  angle; 
  front 
  strongly 
  rounded. 
  Length 
  of 
  valve 
  8 
  mm 
  , 
  

   width 
  3*5 
  mm 
  , 
  the 
  widest 
  portion 
  being 
  near 
  the 
  anterior 
  

   extremity. 
  Beak 
  slightly 
  upcurved, 
  the 
  longitudinal 
  median 
  

   line 
  straight 
  or 
  even 
  slightly 
  concave 
  from 
  the 
  apex 
  of 
  the 
  

   "beak 
  to 
  the 
  middle, 
  where 
  it 
  begins 
  to 
  slope 
  gently 
  to 
  the 
  

   frontal 
  margin 
  ; 
  transverse 
  curvature 
  very 
  slight 
  anteriorly, 
  

   more 
  convex 
  near 
  the 
  beak. 
  

  

  Dorsal 
  valve 
  more 
  convex 
  than 
  the 
  ventral, 
  linguliform 
  ; 
  

   beak 
  depressed, 
  bluntly 
  rounded, 
  curving 
  evenly 
  and 
  gradually 
  

   to 
  the 
  semitruncate 
  anterior 
  margin. 
  

  

  The 
  interior 
  markings 
  of 
  this 
  shell 
  have 
  not 
  been 
  ascertained, 
  

   but 
  the 
  external 
  characters 
  are 
  such 
  as 
  to 
  make 
  a 
  reference 
  to 
  

   the 
  genus 
  Lingulepis 
  more 
  than 
  probably 
  correct. 
  The 
  flat, 
  

   acute-acuminate 
  ventral 
  valve 
  with 
  its 
  elevated 
  or 
  retrorse 
  

   beak, 
  which 
  is 
  not 
  covered 
  by 
  the 
  smaller 
  dorsal 
  shell, 
  is 
  

   peculiarly 
  characteristic 
  of 
  Lingulepis. 
  

  

  There 
  is 
  a 
  form 
  from 
  Texas 
  probably 
  identical 
  with 
  Lingu- 
  

   lella 
  perattenuata 
  that 
  might 
  be 
  mistaken 
  for 
  this 
  species, 
  but 
  

   it 
  is 
  an 
  undoubted 
  Lingulella 
  and 
  does 
  not 
  show 
  the 
  external 
  

   characteristics 
  of 
  Lingtdepis. 
  A 
  comparison 
  of 
  L. 
  meeki 
  with 
  

   the 
  young 
  and 
  narrow 
  specimens 
  of 
  L. 
  acuminata 
  shows 
  it 
  to 
  

   be 
  clearly 
  distinct 
  from 
  that 
  species 
  ; 
  the 
  posterior 
  rostral 
  slopes 
  

   of 
  L. 
  acuminata 
  possess 
  a 
  peculiar 
  incurving 
  which 
  is 
  not 
  

   shown 
  in 
  L. 
  meeki. 
  

  

  Formation 
  and 
  locality. 
  — 
  Middle 
  Cambrian, 
  upper 
  beds 
  of 
  

   Flathead 
  Terrane, 
  Crowfoot 
  Section, 
  Gallatin 
  Range, 
  Yellow- 
  

   stone 
  National 
  Park. 
  

  

  