﻿AHIID.E. 
  3G3 
  

  

  minutus 
  by 
  B. 
  Vetter 
  (MittheiL 
  k. 
  mmeral.-geol. 
  Mus. 
  Dresden, 
  

   pt\ 
  iv. 
  1881, 
  p. 
  116, 
  pi. 
  li. 
  fig. 
  16), 
  also 
  seems 
  to 
  be 
  referable 
  to 
  the 
  

   genus 
  Liodesmus. 
  

  

  Genus 
  MEGALURUS, 
  Agassiz. 
  c 
  Jy^A- 
  

   [Poiss. 
  Foss. 
  vol. 
  ii. 
  pt. 
  i. 
  1^33, 
  p. 
  13.] 
  

  

  Trunk 
  elongate, 
  much 
  laterally 
  compressed. 
  Head 
  large 
  ; 
  all 
  

   the 
  marginal 
  teeth 
  large 
  and 
  conical, 
  but 
  those 
  of 
  the 
  dentary 
  

   largest; 
  inner 
  teeth 
  minute; 
  maxilla 
  laterally 
  compressed 
  and 
  

   much 
  deepened 
  behind 
  ; 
  gular 
  plate 
  present. 
  Vertebral 
  centra 
  

   completely 
  ossified 
  in 
  the 
  adult, 
  biconcave, 
  the 
  hypocentra 
  and 
  

   pleurocentra 
  forming 
  distinct 
  alternating 
  discs 
  in 
  part 
  of 
  the 
  caudal 
  

   region 
  ; 
  ribs 
  short 
  and 
  delicate. 
  Fin-fulcra 
  wanting. 
  1 
  Dorsal 
  fin 
  

   somewhat 
  extended, 
  but 
  not 
  occupying 
  more 
  than 
  the 
  middle 
  third 
  

   of 
  the 
  back 
  ; 
  anal 
  fin 
  small 
  and 
  short-based 
  ; 
  caudal 
  fin 
  with 
  convex 
  

   hinder 
  border. 
  Scales 
  almost 
  oval 
  in 
  shape, 
  the 
  long 
  axis 
  hori- 
  

   zontal. 
  

  

  Megalurus 
  lepidotus, 
  Agassiz. 
  

   1833-44. 
  Megalurus 
  lepidotus, 
  L. 
  Agassiz, 
  Poiss. 
  Foss. 
  vol. 
  ii. 
  pt. 
  i. 
  

  

  p. 
  13 
  ; 
  pt. 
  ii. 
  p. 
  146, 
  pi. 
  li. 
  a. 
  

   1839-41. 
  Megalurus 
  brevicostatus, 
  L. 
  Agassiz, 
  ibid. 
  pt. 
  ii. 
  p. 
  147, 
  pi. 
  li. 
  

  

  fig. 
  3. 
  [Imperfect 
  fish 
  : 
  Palaeontological 
  Museum, 
  Munich.] 
  

   1851. 
  Megalurus 
  lepidotus, 
  A. 
  Wagner, 
  Abh. 
  k. 
  bay. 
  Akad. 
  Wiss., 
  

  

  math.-phys. 
  CI. 
  vol. 
  vi. 
  p. 
  69. 
  

   1851. 
  Megalurus 
  brevicostatus, 
  A. 
  Wagner, 
  ibid. 
  vol. 
  vi. 
  p. 
  70. 
  

   1863. 
  Megalurus 
  lepidotus, 
  A. 
  Wagner, 
  ibid. 
  vol. 
  ix. 
  p. 
  714. 
  

   1863. 
  Megalurus 
  brevicostatus, 
  A. 
  Wagner, 
  ibid. 
  vol. 
  ix. 
  p. 
  719. 
  

   1881. 
  Megalurus 
  brevicostatus, 
  B. 
  Yetter, 
  Mittheil. 
  k. 
  mineral. 
  -geol. 
  

  

  Mus. 
  Dresden, 
  pt. 
  iv. 
  p. 
  116. 
  

  

  Type. 
  Nearly 
  complete 
  fish 
  ; 
  Palaeontological 
  Museum, 
  Munich. 
  

  

  The 
  type 
  species, 
  attaining 
  a 
  length 
  of 
  about 
  0*4. 
  Head 
  with 
  

   opercular 
  apparatus 
  occupying 
  nearly 
  one-quarter 
  of 
  the 
  total 
  length 
  

   of 
  the 
  fish, 
  and 
  the 
  depth 
  of 
  the 
  candal 
  pedicle 
  contained 
  much 
  less 
  

   than 
  five 
  times 
  in 
  the 
  length 
  from 
  the 
  hinder 
  border 
  of 
  the 
  oper- 
  

   culum 
  to 
  the 
  base 
  of 
  the 
  middle 
  caudal 
  fin-rays. 
  Vertebrae 
  about 
  

   45 
  in 
  number, 
  all 
  much 
  deeper 
  than 
  broad, 
  smooth 
  and 
  not 
  indented 
  

   laterally. 
  Dorsal 
  fin 
  comprising 
  about 
  20 
  rays, 
  the 
  distance 
  between 
  

   its 
  origin 
  and 
  the 
  post-temporal 
  bones 
  about 
  equal 
  to 
  that 
  between 
  

  

  1 
  Wagner 
  (Abh. 
  k. 
  bay. 
  Akad. 
  Wiss.. 
  math. 
  -ph 
  vs. 
  CI. 
  vol. 
  is. 
  1863, 
  p. 
  717) 
  

   describes 
  " 
  feinen, 
  borstenartigen 
  Stachelu 
  (fulcra) 
  " 
  on 
  the 
  pelvic 
  fins 
  of 
  the 
  

   so-called 
  M. 
  altivelis. 
  

  

  