﻿PYCNODON-TID^!. 
  

  

  269 
  

  

  1878, 
  pt. 
  ii. 
  p. 
  92, 
  pi. 
  iv. 
  figs. 
  5, 
  6), 
  probably 
  belongs 
  to 
  Coceodus. 
  

   The 
  specimen 
  best 
  displaying 
  the 
  teeth, 
  now 
  in 
  the 
  Stuttgart 
  

   Museum, 
  may 
  even 
  belong 
  to 
  the 
  typical 
  G. 
  armatus, 
  but 
  the 
  teeth 
  

   of 
  its 
  inner 
  flanking 
  series 
  are 
  relatively 
  broader 
  than 
  those 
  in 
  the 
  

   British 
  Museum 
  fossil, 
  no. 
  P. 
  4742. 
  

  

  Genus 
  XENOPHOLIS, 
  Davis. 
  

  

  [Trans. 
  Eoy. 
  Dublin 
  Soc. 
  [2] 
  vol. 
  iii. 
  1887, 
  p. 
  548.] 
  

  

  Trunk 
  comparatively 
  elongated 
  and 
  head 
  large. 
  Head 
  and 
  

   opercular 
  bones 
  ornamented 
  with 
  tubercles 
  and 
  fine 
  ridges, 
  and 
  a 
  

   large, 
  ascending, 
  laterally 
  compressed, 
  bilaterally 
  symmetrical 
  spine 
  

   fixed 
  upon 
  the 
  occipital 
  region 
  of 
  the 
  cranium 
  ; 
  teeth 
  smooth, 
  rounded 
  

   within 
  the 
  mouth, 
  pointed 
  and 
  prehensile 
  in 
  front. 
  Neural 
  and 
  

   haemal 
  arches 
  of 
  axial 
  skeleton 
  of 
  trunk 
  robust, 
  but 
  not 
  expanding 
  

   sufficiently 
  to 
  encircle 
  the 
  notochord. 
  Pelvic 
  fins 
  relatively 
  large 
  ; 
  

   dorsal 
  fin 
  occupying 
  at 
  least 
  the 
  hinder 
  half 
  of 
  the 
  back, 
  and 
  the 
  

   anal 
  somewhat 
  less 
  extended, 
  arising 
  more 
  posteriorly. 
  Abdominal 
  

   region, 
  and 
  middle 
  portion 
  of 
  caudal 
  region, 
  covered 
  with 
  large 
  

   imbricating 
  rhombic 
  scutes, 
  each 
  with 
  one 
  diagonal 
  raised 
  into 
  a 
  

   keel 
  and 
  terminating 
  in 
  a 
  point 
  behind. 
  

  

  The 
  present 
  writer 
  is 
  acquainted 
  only 
  with 
  two 
  specimens 
  refer- 
  

   able 
  to 
  this 
  genus 
  — 
  the 
  type 
  described 
  below, 
  and 
  the 
  other 
  in 
  the 
  

   Court 
  Museum, 
  Vienna. 
  The 
  latter 
  is 
  best 
  preserved, 
  exhibiting 
  

   the 
  occipital 
  spine 
  and 
  part 
  of 
  the 
  dentition. 
  

  

  Xenopholis 
  carinatus, 
  Davis. 
  

  

  1887. 
  Xenopholis 
  carinatus, 
  J. 
  W. 
  Davis, 
  Trans. 
  Roy. 
  Dublin 
  Soc. 
  [2] 
  

   vol. 
  iii. 
  p. 
  549, 
  pi. 
  xxix. 
  fig. 
  4. 
  

  

  Type. 
  Imperfect 
  fish 
  ; 
  British 
  Museum. 
  

  

  The 
  type 
  species, 
  attaining 
  a 
  length 
  of 
  about 
  0-18, 
  as 
  yet 
  imper- 
  

   fectly 
  definable. 
  Dorsal 
  fin 
  with 
  not 
  less 
  than 
  nineteen, 
  anal 
  fin 
  

   with 
  about 
  sixteen 
  rays. 
  Scales 
  relatively 
  large, 
  the 
  dorso-ventral 
  

   series 
  above 
  the 
  origin 
  of 
  the 
  anal 
  fin 
  comprising 
  only 
  eight 
  or 
  nine 
  ; 
  

   those 
  of 
  the 
  caudal 
  region 
  apparently 
  confined 
  to 
  its 
  middle, 
  but 
  

   continued 
  quite 
  to 
  the 
  base 
  of 
  the 
  caudal 
  fin-rays. 
  Each 
  scale 
  

   with 
  a 
  small 
  transverse 
  keel 
  terminating 
  in 
  a 
  median 
  or 
  inferior 
  

   acumination 
  at 
  its 
  hinder 
  margin, 
  and 
  the 
  ornament 
  consisting 
  of 
  

   more 
  or 
  less 
  nodose 
  parallel 
  ridges 
  diverging 
  antero-superiorly 
  

   and 
  antero-inferiorly 
  from 
  this 
  keel; 
  ornament 
  of 
  the 
  external 
  

   bones 
  similarly 
  consisting 
  of 
  nodose 
  ridges 
  or 
  series 
  of 
  acuminate 
  

   tubercles. 
  The 
  ridge 
  -scale 
  at 
  the 
  origin 
  of 
  the 
  anal 
  fin 
  produced 
  

  

  