﻿PYCNODONTID^:. 
  201 
  

  

  37109. 
  Imperfectly 
  preserved 
  similar 
  fish, 
  the 
  head 
  in 
  counterpart 
  

   and 
  displaying 
  part 
  of 
  the 
  left 
  splenial 
  dentition 
  ; 
  Solen- 
  

   hofen. 
  There 
  are 
  traces 
  of 
  the 
  tubercular 
  ornament 
  on 
  

   the 
  scales, 
  and 
  the 
  serration 
  of 
  the 
  ventral 
  ridge-scales 
  is 
  

   conspicuous. 
  H'dberlein 
  Coll. 
  

  

  P. 
  1628. 
  Portion 
  of 
  caudal 
  region 
  of 
  a 
  somewhat 
  larger 
  fish 
  ; 
  

   Kelheim. 
  Egerton 
  Coll. 
  

  

  37107. 
  Small, 
  nearly 
  complete 
  specimen, 
  0-07 
  in 
  lengthen 
  counter- 
  

   part 
  ; 
  Solenhofen. 
  The 
  premaxillse 
  are 
  shown, 
  and 
  the 
  

   course 
  of 
  the 
  dorsal 
  " 
  lateral 
  line 
  " 
  is 
  conspicuous 
  on 
  the 
  

   squamation 
  to 
  the 
  origin 
  of 
  the 
  dorsal 
  fin. 
  Haberlein 
  Coll. 
  

  

  Me 
  so 
  don 
  daviesi, 
  A. 
  S. 
  Woodward. 
  

  

  1890. 
  Mesodon 
  daviesi, 
  A. 
  S. 
  Woodward, 
  Proc. 
  Zool. 
  Soc. 
  1890, 
  p. 
  351, 
  

   pi. 
  xxviii. 
  fig. 
  5. 
  

  

  Type. 
  Nearly 
  complete 
  fish 
  ; 
  British 
  Museum. 
  

  

  A 
  species 
  attaining 
  a 
  length 
  of 
  about 
  0*25. 
  Maximum 
  depth 
  of 
  

   the 
  trunk 
  somewhat 
  less 
  than 
  the 
  length 
  of 
  the 
  head 
  and 
  trunk 
  

   without 
  caudal 
  fin 
  ; 
  distance 
  from 
  frontal 
  angulation 
  to 
  hinder 
  

   margin 
  of 
  preoperculum 
  scarcely 
  exceeding 
  one-fifth 
  of 
  the 
  total 
  

   length 
  of 
  the 
  fish. 
  [Dentition 
  imperfectly 
  known, 
  but] 
  teeth 
  

   smooth, 
  some 
  indented, 
  and 
  those 
  of 
  the 
  principal 
  mandibular 
  series 
  

   at 
  least 
  twice 
  as 
  broad 
  as 
  long. 
  Dorsal 
  and 
  anal 
  fins 
  equally 
  

   elevated, 
  the 
  latter 
  with 
  29 
  rays 
  and 
  four-fifths 
  as 
  long 
  as 
  the 
  

   former, 
  which 
  has 
  38 
  rays. 
  Squamation 
  not 
  covering 
  more 
  than 
  

   half 
  of 
  the 
  trunk. 
  

  

  Form. 
  Sf 
  Log. 
  Purbeckian 
  : 
  Dorsetshire. 
  

  

  41387, 
  P. 
  6381. 
  Type 
  specimen, 
  with 
  incomplete 
  counterpart 
  ; 
  

   Purbeck 
  Beds, 
  Swan 
  age. 
  

  

  Purchased, 
  1869, 
  and 
  Beckles 
  Coll. 
  

  

  P. 
  7454. 
  Remains 
  of 
  head 
  and 
  abdominal 
  region, 
  doubtfully 
  of 
  th 
  

   species 
  ; 
  Swanage. 
  The 
  principal 
  teeth 
  of 
  the 
  mandible 
  

   are 
  more 
  transversely 
  elongated 
  than 
  those 
  in 
  the 
  type 
  

   specimen. 
  History 
  unknown. 
  

  

  P. 
  6383. 
  Portion 
  of 
  caudal 
  region 
  of 
  small 
  fish, 
  probably 
  young 
  of 
  

   this 
  species 
  ; 
  Swanage. 
  Beckles 
  Coll. 
  

  

  The 
  following 
  specimen 
  agrees 
  with 
  the 
  type 
  of 
  Mesodon 
  daviesi 
  

   in 
  the 
  form 
  and 
  proportions 
  of 
  the 
  trunk, 
  but 
  the 
  head 
  is 
  relatively 
  

   as 
  long 
  as 
  in 
  Mesodon 
  macro 
  pterus. 
  The 
  difference 
  is 
  probably 
  due 
  

   to 
  crushing. 
  

  

  