﻿Berry 
  — 
  A 
  Sail 
  Fish 
  from 
  the 
  Virginia 
  Miocene. 
  461 
  

  

  Art. 
  XLI. 
  — 
  A 
  Sail 
  Fish 
  from 
  the 
  Virginia 
  Miocene 
  ; 
  by 
  

  

  Edward 
  W. 
  Berry. 
  

  

  The 
  Paleontological 
  collections 
  of 
  the 
  Johns 
  Hopkins 
  

   University 
  contain 
  two 
  specimens 
  of 
  vertebrate 
  fossils 
  collected 
  

   many 
  years 
  ago 
  from 
  Tar 
  Bay 
  in 
  Virginia 
  and 
  without 
  other 
  

   record 
  than 
  " 
  presented 
  by 
  Mr. 
  Dew." 
  At 
  this 
  locality 
  a 
  few 
  

   feet 
  of 
  Eocene 
  glauconitic 
  marl 
  of 
  the 
  Aquia 
  formation 
  is 
  over- 
  

   lain 
  by 
  a 
  considerable 
  thickness 
  of 
  argillaceous 
  beds 
  of 
  the 
  

   lower 
  part 
  of 
  the 
  Calvert 
  formation. 
  The 
  fossils 
  represent 
  a 
  

   well-preserved 
  tooth 
  of 
  Physeter 
  vetus 
  (Leidy) 
  and 
  a 
  rostrum 
  

   of 
  a 
  new 
  species 
  of 
  Istiophorus. 
  The 
  former 
  is 
  a 
  well-known 
  

   Miocene 
  type 
  and 
  the 
  latter 
  is 
  also 
  considered 
  as 
  coming 
  from 
  

   the 
  same 
  horizon 
  as 
  the 
  tooth, 
  although 
  this 
  is 
  not 
  conclusive. 
  

  

  The 
  genus 
  Istiophorus 
  of 
  Lacepede 
  (numerous 
  authors, 
  as 
  for 
  

   example 
  Smith 
  Woodward, 
  use 
  Histiophorus) 
  comprises 
  several 
  

   existing 
  species 
  of 
  large, 
  elongate, 
  compressed, 
  pelagic 
  fishes 
  

   of 
  warm 
  seas 
  — 
  chiefly 
  Indo-Pacific, 
  but 
  also 
  represented 
  in 
  the 
  

   Atlantic. 
  They 
  are 
  popularly 
  known 
  as 
  Sail 
  fishes 
  because 
  of 
  

   the 
  height 
  of 
  the 
  undivided 
  dorsal 
  fin 
  and 
  have 
  the 
  premaxilla3 
  

   vomer 
  and 
  ethmoid 
  united 
  and 
  produced 
  forward 
  to 
  form 
  a 
  

   rostrum, 
  bony 
  muzzle 
  or 
  sword, 
  which 
  is 
  shorter 
  and 
  rounder 
  

   than 
  that 
  of 
  the 
  closely 
  related 
  more 
  recent 
  and 
  more 
  special- 
  

   ized 
  true 
  sword 
  fishes 
  (Xiphias). 
  

  

  Istiophorus 
  is 
  a 
  convenient 
  name 
  for 
  the 
  rather 
  numerous 
  

   fossil 
  rostra 
  of 
  Istiophorus 
  — 
  or 
  Tetrapturus-like 
  forms, 
  of 
  

   which 
  a 
  number 
  of 
  different 
  types 
  have 
  been 
  recorded 
  from 
  

   strata 
  ranging 
  in 
  age 
  from 
  the 
  Eocene 
  to 
  the 
  Pliocene. 
  

  

  The 
  rostrum, 
  which 
  is 
  more 
  complete 
  and 
  better 
  preserved 
  

   than 
  is 
  usually 
  the 
  case, 
  may 
  be 
  described 
  as 
  follows 
  : 
  

  

  Istiophorus 
  calvertensis, 
  sp. 
  no 
  v. 
  

  

  Bostrum 
  subcylindrical, 
  tapering 
  distad. 
  This 
  tapering 
  is 
  

   gradual 
  when 
  the 
  rostrum 
  is 
  viewed 
  from 
  the 
  side, 
  and 
  con- 
  

   fined 
  to 
  the 
  distal 
  one-third 
  from 
  the 
  dorsal 
  or 
  ventral 
  aspect. 
  

   Bluntly 
  pointed, 
  31 
  cm 
  in 
  length, 
  in 
  general 
  elliptical 
  in 
  transverse 
  

   outline. 
  Surface 
  of 
  anastomosing 
  striae. 
  Dorsal 
  surface 
  dis- 
  

   tinctly 
  less 
  convex 
  than 
  the 
  ventral 
  surface 
  for 
  its 
  anterior 
  two- 
  

   thirds. 
  The 
  anterior 
  third 
  shows 
  scarcely 
  any 
  trace 
  of 
  the 
  

   lateral 
  dorsal 
  furrows 
  wmicli 
  about 
  half 
  way 
  to 
  the 
  base 
  are 
  

   pronounced 
  but 
  not 
  sufficiently 
  emphasized 
  to 
  break 
  the 
  even 
  

   contour 
  of 
  the 
  surface. 
  From 
  the 
  median 
  region 
  backward 
  

   these 
  furrows 
  increase 
  in 
  depth 
  and 
  width, 
  flanking 
  a 
  more 
  

   arched 
  median 
  region, 
  at 
  length 
  becoming 
  toward 
  the 
  base 
  an 
  

   open 
  lateral 
  gutter, 
  the 
  inner 
  limb 
  of 
  which 
  is 
  flattened 
  and 
  

  

  