﻿SEHIONOTID^E. 
  159 
  

  

  1835. 
  Tetragonolepis 
  semieinctus, 
  L. 
  Agassiz, 
  Poiss. 
  Foss. 
  vol. 
  ii. 
  pt. 
  i. 
  

  

  p. 
  196, 
  pi. 
  xxii. 
  figs. 
  2, 
  3. 
  

   1842. 
  Tetragonolepis 
  subserratus, 
  G. 
  von 
  Minister, 
  Neues 
  Jahrb. 
  p. 
  97. 
  

  

  [Imperfect 
  fish 
  ; 
  Paleeontological 
  Museum, 
  Munich.] 
  

   1843. 
  . 
  Tetragonolepis 
  semieinctus, 
  F. 
  A. 
  Quenstedt, 
  Flozgeb. 
  Wiirttemb. 
  

  

  p. 
  240. 
  

  

  1852. 
  Pleurolepis 
  semieinctus, 
  F. 
  A. 
  Quenstedt, 
  Handb. 
  Petrefakt. 
  

   p. 
  214. 
  

  

  1853. 
  Tetragonolepis 
  subserratus 
  =T. 
  semieinctus 
  (?), 
  Sir 
  P. 
  Egerton, 
  

   Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  ix. 
  p. 
  277, 
  pi. 
  xi. 
  fig. 
  3. 
  

  

  1853. 
  Tetragonolepis 
  cyclosoma, 
  Sir 
  P. 
  Egerton, 
  ibid. 
  p. 
  278. 
  [Imperfect 
  

  

  fish 
  ; 
  British 
  Museum.] 
  

   1858. 
  Tetragonolepis 
  semieinctus, 
  F. 
  A. 
  Quenstedt, 
  Der 
  Jura, 
  p. 
  229 
  , 
  

  

  pi. 
  xxix. 
  fig. 
  5. 
  

   1860. 
  Pleurolepis 
  semicincta, 
  A. 
  Wagner, 
  Gelehrte 
  Anzeig. 
  k. 
  bay 
  

  

  Akad. 
  Wiss. 
  vol. 
  1. 
  p. 
  94. 
  

   1883. 
  Pleurolepis 
  semieinctus, 
  F. 
  A. 
  Quenstedt, 
  Handb. 
  Petrefakt. 
  

  

  ed. 
  3, 
  p. 
  323. 
  

   1892. 
  Tetragonolepis 
  semieinctus, 
  0. 
  M. 
  Reis, 
  Geogn. 
  Jahresh. 
  1891, 
  

  

  p. 
  160, 
  fig. 
  11. 
  

  

  Type. 
  Fish, 
  imperfect 
  anteriorly. 
  

  

  The 
  type 
  species, 
  attaining 
  a 
  length 
  of 
  about 
  0*1. 
  The 
  maximum 
  

   depth 
  of 
  the 
  trunk 
  five 
  times 
  as 
  great 
  as 
  the 
  depth 
  of 
  the 
  caudal 
  

   pedicle, 
  and 
  contained 
  one-and-a-half 
  times 
  in 
  the 
  total 
  length 
  of 
  

   the 
  fish 
  ; 
  the 
  greatest 
  depth 
  of 
  that 
  portion 
  of 
  the 
  trunk 
  below 
  the 
  

   vertebral 
  axis 
  equalling 
  about 
  three 
  times 
  that 
  of 
  the 
  portion 
  above 
  

   the 
  axis. 
  Head 
  with 
  opercular 
  apparatus 
  occupying 
  nearly 
  one- 
  

   quarter 
  of 
  the 
  total 
  length 
  ; 
  external 
  bones 
  feebly 
  tuberculated 
  ; 
  

   marginal 
  teeth 
  slender. 
  Scales 
  smooth, 
  or 
  with 
  slight 
  rugse 
  following 
  

   the 
  concentric 
  lines 
  of 
  growth, 
  the 
  hinder 
  border 
  serrated 
  ; 
  those 
  

   of 
  the 
  flanks 
  very 
  deep, 
  and 
  the 
  ventral 
  ridge-scales 
  finely 
  denticu- 
  

   lated. 
  

  

  The 
  best 
  figure 
  of 
  this 
  species 
  hitherto 
  published 
  is 
  given 
  by 
  

   Quenstedt, 
  Der 
  Jura, 
  pi. 
  xxix. 
  fig. 
  5. 
  

  

  Form. 
  Sf 
  Log. 
  Upper 
  Lias 
  : 
  Wiirtemberg 
  and 
  Bavaria. 
  

  

  16369. 
  Imperfect 
  head 
  and 
  trunk 
  with 
  remains 
  of 
  the 
  paired 
  fins 
  ; 
  

   Ohmden, 
  near 
  Boll, 
  Wurtemberg. 
  The 
  squamation 
  is 
  

   almost 
  entirely 
  removed 
  in 
  the 
  caudal 
  region, 
  and 
  some 
  of 
  

   the 
  laminar 
  appendages 
  of 
  the 
  neural 
  spines 
  are 
  shown. 
  

  

  Purchased, 
  1842. 
  

  

  22524. 
  Similar 
  specimen 
  wanting 
  all 
  the 
  fins, 
  but 
  displaying 
  some 
  

   of 
  the 
  teeth 
  ; 
  Boll. 
  Appearances 
  in 
  the 
  axial 
  skeleton 
  of 
  

   the 
  trunk 
  suggest 
  either 
  that 
  the 
  neural 
  and 
  haemal 
  

  

  