A  NEW  GENUS  OF  ACANTHOPTERYGIAN  FISHES. 
127 
seventeen  rays,  the  three  anterior  of  which  are  simple.  The  first  seven  exceed  very 
considerably  in  length  those  which  succeed  them,  and  the  fin  at  this  point  decreases  sud- 
denly in  height ;  the  remaining  rays  are  all  nearly  of  equal  length  with  each  other,  and 
httle  more  than  one  fourth  of  the  length  of  the  first  ray. 
The  ventral  fins  are  placed  rather  nearer  to  the  pectoral  than  to  the  anal.  They  re- 
semble the  pectoral  in  form  ;  but  are  not  quite  one  half  of  their  length.  Each  is  sup- 
ported by  nine  rays,  the  first  of  which  is  simple  and  slightly  scabrous. 
The  amis  is  situated  a  short  distance  behind  the  ventral  fins,  and  is  exactly  inter- 
mediate between  the  pectoral  and  the  commencement  of  the  anal. 
The  lateral  line  commences  near  the  base  of  the  anterior  ray  of  the  first  dorsal  fin  ; 
descends  gradually  to  the  middle  of  the  side ;  and  is  continued  to  the  base  of  the 
caudal  fin.  Its  hinder  portion,  and  consequently  the  tail,  is  destitute  of  any  particular 
armour. 
The  above  description  is  taken  from  the  specimen  first  captured,  which  is  now  in 
the  Museum  of  the  Zoological  Society,  with  occasional  reference  to  the  second  spe- 
cimen (the  one  figured)  for  parts  which  are  in  the  other  more  or  less  mutilated.  The 
length  of  the  original  specimen,  which  is  somewhat  the  largest,  is  nearly  5  feet. 
Between  the  two  individuals  there  are  some  differences  in  the  number  of  the  teeth, 
which  it  is  desirable  to  mention.  The  posterior  series  of  palatine  teeth,  which  in  one 
consists  of  six,  is  extended  in  the  other  to  eight  on  each  side ;  and  in  this  latter  spe- 
cimen there  is,  on  one  side,  a  single  small  tooth  remaining  in  the  hinder  portion  of 
the  palatine  bone  which  in  the  first  is  altogether  unarmed.  In  the  lower  jaw  of  this 
second  individual  the  number  of  the  smaller  teeth  immediately  succeeding  the  anterior 
one  is  also  greater  than  in  the  first,  the  series  consisting  of  nine,  instead  of  six,  on 
each  side.  These  differences  may  be  regarded  as  of  minor  importance,  and  as  pro- 
bably dependent  on  the  accidental  removal  of  some  of  the  teeth,  to  which  (from  their 
extremely  penetrating  character  and  retral  direction)  these  organs  must  be  peculiarly 
liable  in  a  fish  of  such  ferocious  habits. 
A  second  difference  between  these  individuals  has  been  already  mentioned  in  the 
description :  it  seems,  however,  deserving  of  more  formal  notice,  as  it  has  hitherto 
been  generally  considered  by  ichthyologists  that  the  number  of  the  rays  of  the  branchi- 
ostegous  membrane  might  be  regarded  as  offering  a  fixed  character,  even  in  a  natural 
genus :  its  fixity  in  a  species  ought  consequently  to  be  looked  upon  as  altogether  un- 
questionable. In  the  present  instance,  however,  the  number  differs  in  the  only  two 
specimens  yet  seen.  In  one  there  are  six,  and  in  the  other  seven,  rays  of  the  bran- 
chiostegous  membrane.  On  comparison  of  the  specimens  it  would  seem  that  in  the 
one  which  has  the  smallest  number  of  rays,  the  deficiency  occurs  among  the  anterior 
of  them,  the  extent  of  the  membrane  supported  by  its  first  two  rays  being  about  equal 
to  that  which  is  supported  in  the  other  by  three.  The  occurrence  is  probably  to  be 
regarded  in  the  light  of  a  monstrosity  merely. — E.  T,  B.] 
