﻿PACHYCOKMID^. 
  413 
  

  

  P. 
  1482 
  a. 
  Another 
  similar 
  specimen 
  ; 
  English 
  Chalk. 
  

  

  Egerton 
  Coll. 
  

  

  25846. 
  Fragment 
  of 
  fin 
  ; 
  Chalk, 
  Sussex. 
  Dixon 
  Coll. 
  

  

  49817. 
  Another 
  small 
  fragment 
  ; 
  Chalk, 
  Amberley. 
  C 
  apron 
  Coll. 
  

  

  The 
  following 
  specimens 
  are 
  more 
  doubtfully 
  assigned 
  to 
  Proto- 
  

   sphyrcena 
  :- 
  — 
  

  

  4077. 
  Anterior 
  portion 
  of 
  fin 
  described 
  and 
  figured 
  by 
  Agassiz 
  

   (op. 
  cit. 
  vol. 
  iii. 
  p. 
  59, 
  pi. 
  x. 
  b. 
  fig. 
  18) 
  under 
  the 
  name 
  of 
  

   Ptychodus 
  ; 
  Chalk, 
  Lewes. 
  Mantell 
  Coll. 
  

  

  25846 
  a. 
  Fragment 
  figured 
  as 
  Ptychodus 
  in 
  Dixon's 
  Geol. 
  Sussex, 
  

   pi. 
  xxxi. 
  fig. 
  14 
  ; 
  Chalk, 
  Sussex. 
  Dixon 
  Coll. 
  

  

  P. 
  7573. 
  Very 
  imperfect 
  pectoral 
  fin 
  showing 
  seven 
  basals 
  and 
  

   other 
  bones 
  ; 
  English 
  Chalk. 
  History 
  unknown. 
  

  

  The 
  so-called 
  Ptychodus 
  articulatus, 
  Agassiz 
  (op. 
  cit. 
  vol. 
  iii. 
  p. 
  58, 
  

   pi. 
  x. 
  a. 
  figs. 
  5, 
  6) 
  seems 
  to 
  be 
  a 
  fragment 
  of 
  the 
  caudal 
  fin 
  of 
  

   Poriheus 
  or 
  an 
  allied 
  fish. 
  The 
  appearance 
  of 
  a 
  wavy 
  margin 
  given 
  

   in 
  Agassiz's 
  figure 
  is 
  imaginary. 
  

  

  The 
  following 
  specimen 
  probably 
  belongs 
  to 
  the 
  family 
  Pachy- 
  

   cormidse, 
  if 
  not 
  to 
  the 
  genus 
  Protosphyrcena 
  itself 
  : 
  — 
  

  

  49531. 
  Middle 
  portion 
  of 
  caudal 
  region 
  noticed 
  in 
  Ann. 
  Mag. 
  Nat. 
  

   Hist. 
  [6] 
  vol. 
  xiii. 
  (1894), 
  p. 
  512 
  ; 
  Upper 
  Cretaceous, 
  

   Sahel-el-Alma, 
  Mt. 
  Lebanon. 
  There 
  are 
  no 
  traces 
  of 
  

   vertebral 
  centra, 
  but 
  the 
  arches 
  are 
  very 
  numerous 
  and 
  

   well 
  ossified, 
  somewhat 
  expanded 
  at 
  the 
  base. 
  Eemains 
  

   of 
  a 
  dorsal 
  fin 
  occur 
  in 
  advance 
  of 
  a 
  smaller 
  anal. 
  Fos- 
  

   silized 
  remains 
  of 
  the 
  muscular 
  fibres 
  are 
  also 
  conspicuous. 
  

  

  Leivis 
  Coll. 
  

  

  An 
  imperfect 
  and 
  abraded 
  rostrum 
  from 
  the 
  Cretaceous 
  (Niobrara 
  

   Group) 
  of 
  Kansas 
  is 
  also 
  referred 
  to 
  this 
  genus 
  under 
  the 
  name 
  of 
  

   Erisichihe 
  ziphioides 
  by 
  E. 
  D. 
  Cope, 
  Bull. 
  U.S. 
  Geol. 
  Surv. 
  Territ. 
  

   vol. 
  iii. 
  (1877), 
  p. 
  823. 
  Fragments 
  of 
  jaws 
  from 
  the 
  Cretaceous 
  of 
  

   North 
  Carolina 
  are 
  provisionally 
  placed 
  here 
  (Portheus 
  angulatus, 
  

   E. 
  D. 
  Cope, 
  Proc. 
  Acad. 
  Nat. 
  Sci. 
  Philad. 
  1872, 
  p. 
  281, 
  and 
  in 
  

   Kerr's 
  Rep. 
  Geol. 
  Surv. 
  N. 
  Carolina, 
  1875, 
  Append. 
  B, 
  p. 
  32 
  ; 
  

   Erisichihe 
  angulata, 
  E. 
  D. 
  Cope, 
  Yert. 
  Cret. 
  Form. 
  West, 
  1875, 
  

   p. 
  275). 
  

  

  Pectoral 
  fins 
  of 
  undetermined 
  species 
  of 
  Protosphyrcena 
  were 
  

  

  