A  NEW  GENUS  OF  ACANTIIOPTERYGIAN  FISHES. 
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measure  one  seventh  of  tlie  total  length ;  the  height  of  the  head  is  one  half  of  its 
length.  The  head  is  compressed  on  the  sides  and  flat  above.  Its  upper  surface  is 
narrow,  the  breadth  of  the  cranium  behind  the  eyes  being  scarcely  one  fifth  of  its 
length :  from  behind  the  eyes  it  becomes  gradually  narrower  as  it  advances  forwards 
to  the  nose,  which  is  almost  pointed.  This  surface  is  irregularly  striated  by  ridges  of 
bone,  covered  only  by  a  thin  skin,  which  radiate  on  each  side  from  a  point  above  the 
orbit.  At  the  junction  of  the  upper  surface  with  the  flattened  sides  of  the  head  a 
strong  keel  or  ridge  is  formed.  In  the  small  space  intervening  between  this  keel  and 
the  orbit  the  bone  is  cavernous,  forming  at  its  lower  part,  just  behind  the  eye,  a  re- 
markable prominence.  From  behind  this  prominence  there  pass  downwards  to  near 
the  angle  of  the  mouth,  a  series  of  small  bones,  producing  on  the  smooth  skin  the  ap- 
pearance of  a  double  row  of  lengthened  tubercles.  The  prasoperculum  is  simple,  forming 
a  right  angle  with  the  upper  line  of  the  head.  The  operculum  and  suboperculum  are 
strongly  striated  in  a  radiating  manner.  From  the  lower  part  of  the  series  of  small 
bones  above  noticed,  the  suborbital  bones  extend  forwards  to  the  nose  in  a  narrow  two- 
ridged  line.  The  maxillary  bone  forms  a  line  nearly  parallel  to  the  last ;  is  situated, 
like  it,  beneath  the  skin ;  and  borders  the  intermaxillary  which  constitutes  the  edge  of 
the  mouth. 
The  intermaxillary  bone  on  each  side  is  slender  and  slightly  toothed  throughout  its 
whole  length  :  the  anterior  teeth,  about  six  in  number,  are  conical  and  stronger  than  the 
remainder  ;  those  immediately  succeeding  are  very  small  and  very  numerous  ;  they  are 
followed  by  others  of  a  larger  size  (but  smaller  than  the  anterior  ones),  to  the  number 
of  about  one  hundred  and  ten,  forming  a  single  series,  and  resembling  the  teeth  of  a 
fine  saw.  The  palatine  bones,  extending  forwards  to  the  front  of  the  mouth  and  lying 
immediately  within  the  intermaxillaries,  are  armed  with  very  large  and  powerful  lancet- 
shaped  teeth,  all  of  which  have  their  points  directed  backwards.  The  anterior  of  these 
teeth  are  the  largest :  they  equal  in  length  one  sixth  of  the  entire  length  of  the  head. 
Of  these  there  remain  two  on  one  side  and  one  on  the  other ;  and  it  is  probable  that 
their  number  has  been  two  only  on  each  side.  Behind  these,  at  an  interval  nearly  equal 
to  their  length,  succeed  two  teeth  on  each  side,  about  half  the  size  of  the  preceding. 
These  are  followed  by  six  others  of  much  smaller  size,  of  which  the  anterior  is  the 
least ;  they  gradually  increase  in  size,  and  the  last  of  them  is  about  one  third  of  the 
length  of  the  tooth  immediately  preceding  the  series.  The  posterior  unarmed  portion 
of  the  palatine  bone  in  advance  of  the  gape  is  about  one  eighth  of  the  length. 
The  lower  jaw  ceases  to  be  armed  nearly  at  the  corresponding  point.  Its  teeth,  like 
those  of  the  upper,  are  lancet-shaped.  The  anterior  tooth  is  somewhat  conical  and 
is  sharply  pointed.  It  is  succeeded  by  six  others,  of  more  compressed  form,  and  of 
smaller  size.  These  are  followed  by  three  large  lancet-shaped  teeth,  increasing  in  size 
backwards,  the  hindermost  equalling  the  largest  of  the  two  intermediate  ones  of  the 
upper  jaw.    These  three  larger  teeth  correspond,  when  the  mouth  is  closed,  with  the 
s  2 
