﻿PACELYCORMnLE. 
  

  

  399 
  

  

  of 
  the 
  caudal 
  fin 
  the 
  expanded 
  supporting 
  haemal 
  spine 
  

   is 
  conspicuous, 
  and 
  there 
  is 
  a 
  slight 
  longitudinal 
  ridge 
  on 
  

   this 
  bone 
  where 
  the 
  rays 
  of 
  the 
  upper 
  and 
  lower 
  lobes 
  

   diverge. 
  A 
  few 
  uniserial 
  fulcra 
  are 
  intercalated 
  between 
  

   the 
  tips 
  of 
  the 
  gradually 
  lengthening 
  rays 
  on 
  the 
  anterior 
  

   borders 
  of 
  the 
  fin. 
  All 
  the 
  scales 
  preserved 
  both 
  behind 
  

   the 
  pectoral 
  arch 
  and 
  at 
  the 
  origin 
  of 
  the 
  caudal 
  fin 
  are 
  

   ornamented 
  with 
  very 
  fine 
  tubercles. 
  Leeds 
  Coll. 
  

  

  P. 
  6920. 
  Expanded 
  haemal 
  arch 
  from 
  base 
  of 
  caudal 
  fin 
  either 
  of 
  

   this 
  or 
  the 
  preceding 
  species 
  ; 
  near 
  Peterborough. 
  

  

  Leeds 
  Coll. 
  

  

  The 
  following 
  specimens 
  are 
  not 
  specifically 
  determined 
  : 
  — 
  

  

  42368 
  a, 
  43028 
  a, 
  P. 
  347 
  a. 
  Five 
  fragments 
  of 
  jaws 
  of 
  a 
  small 
  

   species, 
  noticed 
  in 
  Geol. 
  Mag. 
  [3] 
  vol. 
  vi. 
  1889, 
  p. 
  451 
  ; 
  

   Kimmeridge 
  Clay, 
  Weymouth. 
  

  

  Purchased, 
  1870, 
  1871, 
  1881. 
  

  

  P. 
  6918. 
  Two 
  very 
  stout 
  left 
  maxillae, 
  more 
  or 
  less 
  imperfect 
  ; 
  

   Oxford 
  Clay, 
  near 
  Peterborough. 
  Leeds 
  Coll. 
  

  

  36308. 
  Expanded 
  haemal 
  arch 
  from 
  base 
  of 
  caudal 
  fin, 
  associated 
  

   with 
  fragments 
  of 
  rays 
  ; 
  Oxford 
  Clay, 
  Christian 
  Malford, 
  

   Wiltshire. 
  Purchased. 
  1861. 
  

  

  Genus 
  PROTOSPHYR-ffiNA, 
  Leidy. 
  

  

  [Trans. 
  Amer. 
  Phil. 
  Soc. 
  vol. 
  xi. 
  1857, 
  p. 
  95.] 
  

  

  Syn. 
  Erisichthe, 
  E. 
  D. 
  Cope, 
  Proc. 
  Acad. 
  Nat. 
  Sci. 
  Philad. 
  1872, 
  

   p. 
  280. 
  

   Pelecopterus, 
  E. 
  D. 
  Cope, 
  Vert. 
  Cret. 
  Form. 
  West. 
  (Rep. 
  U.S. 
  

   Geol. 
  Surv. 
  Territ. 
  vol. 
  ii. 
  1875), 
  p. 
  244 
  c. 
  

  

  An 
  imperfectly 
  definable 
  genus 
  known 
  only 
  by 
  the 
  head, 
  pectoral 
  

   arch, 
  and 
  pectoral 
  fins, 
  which 
  are 
  closely 
  similar 
  to 
  the 
  corresponding 
  

   parts 
  of 
  Hypsocormus. 
  Rostrum 
  ordinarily 
  much 
  produced 
  ; 
  pre- 
  

   m 
  axilla 
  large 
  and 
  triangular 
  in 
  shape. 
  Dentition 
  powerful, 
  all 
  the 
  

   principal 
  teeth 
  much 
  compressed, 
  with 
  sharp 
  anterior 
  and 
  posterior 
  

   edges, 
  and 
  fixed 
  in 
  deep, 
  complete 
  sockets 
  ; 
  those 
  of 
  the 
  vomer, 
  

   premaxilla, 
  and 
  splenial 
  especially 
  large, 
  and 
  similar 
  teeth 
  pro- 
  

   jecting 
  forwards 
  from 
  the 
  downwardly-curved 
  anterior 
  extremity 
  

   of 
  the 
  oral 
  border 
  of 
  the 
  dentary 
  ; 
  those 
  of 
  the 
  maxilla 
  and 
  hinder 
  

   portion 
  of 
  dentary 
  comparatively 
  small 
  and 
  in 
  a 
  single 
  close 
  series 
  ; 
  

  

  