﻿100 
  

  

  1^'TE0DUCTI0X. 
  

  

  extremely 
  difficult 
  to 
  discern 
  tlie 
  limit 
  between 
  the 
  

   two. 
  The 
  term 
  •'* 
  body 
  " 
  is. 
  therefore, 
  used 
  in 
  the 
  

   description 
  as 
  meaning 
  both 
  head 
  and 
  body. 
  Its 
  lon- 
  

   ofitudinal 
  measurement 
  is 
  taken 
  to 
  the 
  orio^in 
  of 
  the 
  

   hind 
  limbs. 
  The 
  tail 
  consists 
  of 
  a 
  fleshj 
  muscular 
  

   portion 
  bordered 
  above 
  and 
  below 
  bj 
  membranous 
  

   expansions, 
  termed 
  respectively 
  the 
  upper 
  and 
  lower 
  

   crest. 
  By 
  depth 
  of 
  the 
  tail 
  is 
  meant 
  its 
  greatest 
  

   depth, 
  crests 
  included, 
  and 
  the 
  length 
  is 
  measured 
  

   from 
  the 
  posterior 
  extremity 
  of 
  the 
  body. 
  

  

  Mouth 
  (Fig. 
  42). 
  — 
  This 
  term 
  is 
  used 
  in 
  its 
  wider 
  

   sense, 
  i. 
  e. 
  to 
  include 
  the 
  much-developed 
  lip 
  surround- 
  

   ing, 
  like 
  a 
  funnel 
  directed 
  downwards, 
  the 
  horny 
  beak, 
  

   not 
  unlike 
  that 
  of 
  a 
  cuttle-fisli, 
  which 
  forms 
  tlie 
  

   entrance 
  to 
  the 
  motith 
  proper. 
  The 
  characters 
  offered 
  

   by 
  this 
  circular 
  lip 
  are 
  among 
  the 
  most 
  important 
  for 
  

   the 
  distinction 
  of 
  species. 
  The 
  lip 
  may 
  be 
  entirely 
  

   bordered 
  by 
  fleshy 
  papilla? 
  (I 
  •}).), 
  or 
  these 
  may 
  be 
  re- 
  

   stricted 
  to 
  the 
  sides, 
  or 
  to 
  

   the 
  sides 
  and 
  the 
  lower 
  

   border. 
  Its 
  inner 
  surface 
  

   is 
  furnished 
  with 
  ridges 
  

   armed 
  with 
  series 
  of 
  

   minute 
  bristle-like 
  erect 
  

   horny 
  teeth 
  (f), 
  each 
  of 
  

   which. 
  when 
  strongrlv 
  

   magnified, 
  is 
  seen 
  to 
  be 
  

   formed 
  of 
  a 
  column 
  of 
  

   superposed 
  cones, 
  hol- 
  

   lowed 
  out 
  at 
  the 
  base 
  

   B 
  and 
  capping 
  each 
  other 
  

  

  Homj 
  teeth 
  of 
  Barm 
  agilis 
  (a) 
  (Fig. 
  43) 
  ; 
  the 
  Summit 
  or 
  

   a.nd 
  PelohatesfiiscnsiB). 
  (After 
  crOWn 
  of 
  each 
  of 
  these 
  

   Yan 
  Bambeke.) 
  . 
  i 
  i 
  i^ 
  

  

  cones 
  IS 
  expandea, 
  spatu- 
  

   late, 
  hooked 
  backwards, 
  and 
  usually 
  multicuspid. 
  

   The 
  denticles 
  are 
  absent 
  in 
  Felohates 
  and 
  PeJodytes, 
  

   and 
  present 
  in 
  all 
  the 
  other 
  genera. 
  The 
  number 
  of 
  

   these 
  columns 
  is 
  very 
  great. 
  F. 
  E. 
  Schulze 
  has 
  

   counted 
  as 
  many 
  as 
  1100 
  in 
  the 
  lip 
  of 
  Pelohates 
  fiiscus. 
  

  

  