﻿AND 
  AVES 
  OF 
  NORTH 
  AMERICA. 
  

  

  85 
  

  

  wider 
  than 
  long 
  ; 
  in 
  our 
  specimens 
  and 
  Gray's 
  figure 
  it 
  is 
  nearly 
  twice 
  as 
  wide 
  as 
  long. 
  It 
  also 
  appears 
  that 
  the 
  

   nasal 
  bones 
  do 
  not 
  entirely 
  divide 
  the 
  nasal 
  meatus, 
  which 
  they 
  do 
  in 
  the 
  three 
  specimens 
  under 
  observation. 
  On 
  the 
  

   whole 
  I 
  am 
  disposed 
  to 
  think 
  that 
  these 
  forms 
  belong 
  to 
  one 
  rather 
  variable 
  species. 
  It 
  is 
  true 
  that 
  Gray 
  says 
  "hind 
  

   foot 
  fringed," 
  but 
  this 
  I 
  am 
  inclined 
  to 
  think 
  must 
  be 
  true 
  to 
  a 
  very 
  limited 
  extent. 
  There 
  is 
  only 
  a 
  keel 
  in 
  our 
  

   specimen, 
  and 
  Lilljeborg 
  says 
  there 
  is 
  no 
  fringe 
  in 
  his. 
  

  

  OSTEOLAEMUS 
  TETRASPES, 
  Cope. 
  

   Proceed. 
  Ac. 
  N. 
  Sci., 
  Phila., 
  1860, 
  550. 
  

  

  Fig. 
  25. 
  

  

  Fig. 
  26. 
  

  

  Crocodilus 
  palpebrosus, 
  var. 
  2, 
  Cuvier. 
  Oss. 
  Foss. 
  iii., 
  t. 
  2 
  f. 
  6 
  (part). 
  

   Crocodilus 
  trigonatus 
  (part) 
  Curvier. 
  Oss. 
  Foss. 
  iii., 
  65. 
  

  

  African 
  Black 
  Crocodile, 
  Gray. 
  Eept. 
  British 
  

   Assoc, 
  1862, 
  Zool. 
  Section, 
  107. 
  

  

  Osteolaemus 
  tetraspes, 
  Cope. 
  Proc. 
  Acad. 
  N. 
  

   S., 
  Phila,, 
  xii., 
  550. 
  

  

  Crocodilus 
  frontatus, 
  A.Murray. 
  Proc. 
  Zool. 
  

   Soc, 
  1862, 
  pp. 
  139, 
  213, 
  fig. 
  head, 
  t. 
  29, 
  by 
  Ford. 
  

   Strauch, 
  Syn. 
  Cro., 
  t. 
  I., 
  head 
  (young). 
  

  

  Halcrosia 
  frontata, 
  Gray, 
  Ann 
  and 
  Mag. 
  Nat. 
  

   Hist., 
  3d 
  series, 
  X., 
  277. 
  

  

  Halcrosia 
  afzelii 
  Lilljeborg. 
  Proceed. 
  Zool. 
  

   Soc, 
  London., 
  1867, 
  715. 
  

  

  Habitat, 
  Gaboon 
  Ogobai 
  (Duchaillu). 
  

   Calabar 
  (Murray), 
  Sierra 
  Leon 
  (Afzelius). 
  

   This 
  species 
  was 
  originally 
  characterized 
  as 
  

   follows 
  : 
  

  

  Proportions 
  of 
  the 
  head 
  somewhat 
  similar 
  to 
  

   those 
  of 
  Crocodilus 
  trigonops, 
  Gray, 
  of 
  India. 
  

   Breadth 
  of 
  muzzle 
  at 
  ninth 
  tooth 
  equal 
  to 
  the 
  dis- 
  

   tance 
  between 
  the 
  external 
  nasal 
  orifice 
  and 
  anterior 
  border 
  of 
  the 
  orbit, 
  and 
  to 
  the 
  width 
  of 
  the 
  table 
  of 
  the 
  

   cranium 
  posteriorly. 
  A 
  short 
  ridge 
  in 
  front 
  of 
  each 
  orbit, 
  directed 
  obliquely 
  inward. 
  

  

  Teeth 
  }f 
  , 
  rather 
  compressed. 
  Four 
  nuchal 
  shields, 
  in 
  a 
  single 
  transverse 
  series 
  ; 
  four 
  cervicals 
  in 
  pairs 
  ; 
  Dorsal 
  

   shields 
  in 
  six 
  rows. 
  Posterior 
  extremities 
  without 
  fringe. 
  Total 
  length 
  of 
  the 
  entire 
  specimen, 
  five 
  feet. 
  

  

  In 
  addition 
  to 
  the 
  characters 
  given 
  above 
  maybe 
  mentioned 
  the 
  strong 
  concavity 
  of 
  the 
  muzzle 
  in 
  the 
  longitudinal 
  

   direction, 
  and 
  the 
  prominence 
  of 
  the 
  nares. 
  The 
  margins 
  of 
  the 
  maxillary 
  are 
  very 
  sinuous, 
  being 
  much 
  contracted 
  

   behind 
  the 
  fourth 
  and 
  eleventh 
  teeth. 
  The 
  derm 
  of 
  the 
  head 
  is 
  thin 
  and 
  corneous, 
  and 
  divided 
  into 
  many 
  segments, 
  

   which 
  have 
  a 
  fine 
  sculpture 
  of 
  straight 
  lines 
  radiating 
  from 
  the 
  centre 
  in 
  each. 
  The 
  bones 
  of 
  the 
  cranium 
  are 
  very 
  

   strongly 
  pitted. 
  Seventeen 
  transverse 
  series 
  of 
  plates 
  between 
  nape 
  and 
  posterior 
  line 
  of 
  femora, 
  12 
  to 
  union 
  of 
  

   lateral 
  caudal 
  crests, 
  and 
  19 
  from 
  that 
  point 
  to 
  end 
  of 
  tail. 
  Nineteen 
  cross-rows 
  of 
  large 
  plates 
  from 
  ankle 
  joint 
  to 
  

   groin, 
  on 
  anterior 
  face 
  of 
  limb. 
  Counting 
  similarly 
  on 
  the 
  fore 
  limb, 
  there 
  are 
  13 
  series. 
  Only 
  the 
  two 
  lateral 
  dorsal 
  

   keeled 
  ; 
  keels 
  of 
  the 
  outer 
  of 
  the 
  first 
  eight 
  caudal 
  annuli, 
  low. 
  

  

  Color 
  everywhere 
  black 
  ; 
  the 
  plates 
  occasionally 
  with 
  irregular 
  olive 
  lines. 
  The 
  young, 
  according 
  to 
  Murray, 
  

   have 
  olive 
  bands 
  on 
  a 
  yellow-brown 
  ground, 
  including 
  two 
  bands 
  of 
  plates, 
  and 
  separated 
  by 
  two 
  bands. 
  Total 
  

   length, 
  five 
  feet 
  ; 
  muzzle 
  to 
  supraoccipital 
  ridge, 
  8 
  in. 
  9 
  lin. 
  ; 
  do. 
  to 
  posterior 
  margin 
  thighs, 
  2 
  ft. 
  7.6 
  in. 
  

  

  Gray 
  supposes 
  this 
  to 
  be 
  the 
  " 
  Crokodil 
  noir 
  du 
  niger" 
  of 
  Adanson, 
  and 
  hence 
  cites 
  as 
  its 
  earliest 
  name 
  Croco- 
  

   dihis 
  niger 
  Latreille. 
  Dr. 
  Strauch, 
  however, 
  shows 
  that 
  this 
  is 
  probably 
  the 
  Crocodilus 
  calaphractus 
  Cuvier, 
  and 
  I 
  

   have 
  pointed 
  out 
  that 
  it 
  cannot 
  be 
  the 
  species 
  of 
  Latreille. 
  

  

  AMERI. 
  PHTLOSO. 
  SOC. 
  — 
  VOL. 
  XIV. 
  22 
  

  

  