﻿236 
  THE 
  EXTINCT 
  BATRACHIA, 
  REPTILIA 
  

  

  Class 
  III.-A^ES. 
  

  

  TOTIPALMATI. 
  

  

  SULA, 
  Brisson. 
  

  

  SULA 
  LOXOSTYLA, 
  Cope. 
  

   Spec. 
  nov. 
  fig. 
  53. 
  

  

  This 
  species 
  is 
  established 
  on 
  a 
  single 
  coracoid 
  bone 
  which 
  I 
  found 
  at 
  the 
  foot 
  of 
  the 
  Miocene 
  cliffs 
  in 
  Calvert 
  Co., 
  

   Maryland. 
  The 
  furcular 
  articular 
  surface 
  is 
  broken 
  off, 
  as 
  well 
  as 
  the 
  exterior 
  half 
  of 
  the 
  posterior 
  or 
  sternal 
  articu- 
  

   lar 
  extremity. 
  The 
  extremity 
  of 
  the 
  scapular 
  surface 
  is 
  also 
  injured. 
  Sufficient 
  of 
  the 
  bone 
  remains 
  to 
  furnish 
  many 
  

   characteristic 
  peculiarities, 
  and 
  indicate 
  its 
  affinity 
  to 
  the 
  totipahnate 
  family 
  of 
  the 
  Gannetts 
  or 
  Sulidae. 
  

  

  The 
  bone 
  is 
  stout, 
  and 
  indicates 
  a 
  bird 
  of 
  strong 
  flight. 
  The 
  shaft 
  proper 
  is 
  rather 
  short, 
  and 
  sub-cylindric, 
  with 
  

   a 
  trihedral 
  tendency. 
  This 
  form, 
  with 
  the 
  expanded 
  distal 
  extremity, 
  indicates 
  its 
  wide 
  distinction 
  from 
  the 
  cora- 
  

   coid 
  of 
  the 
  Gallinaceae. 
  Its 
  sub-cylindric 
  shaft 
  marks 
  considerable 
  difference 
  from 
  the 
  Lamellirostres 
  and 
  many 
  other 
  

   aquatic 
  types. 
  Its 
  lack 
  of 
  inner 
  subclavicular 
  ala 
  and 
  foramen, 
  distinguishes 
  the 
  type 
  from 
  Rapt 
  ores, 
  the 
  majority 
  of 
  

   Fig. 
  53. 
  , 
  . 
  Longipennes 
  and 
  many 
  Grallse. 
  The 
  presence 
  of 
  a 
  marginal 
  groove 
  or 
  rabbett 
  distinguishes 
  

   r 
  Ssrrrmk 
  it 
  not 
  only 
  from 
  most 
  Psittaci 
  and 
  Insessors, 
  but 
  from 
  many 
  Natatores 
  also. 
  After 
  a 
  study 
  of 
  

  

  Jrwk 
  m*mk 
  ^ 
  le 
  l 
  ar 
  S 
  e 
  collection 
  of 
  bird 
  skeletons 
  in 
  the 
  Museum 
  of 
  the 
  Academy 
  Natural 
  Sciences, 
  aided 
  by 
  

  

  «w 
  * 
  . 
  the 
  Oissaux 
  Fossiles 
  of 
  A. 
  Milne 
  Edwards, 
  I 
  find 
  it 
  resembles 
  closely 
  the 
  genus 
  Sula. 
  

  

  wil 
  illtlr 
  ^k 
  e 
  glenoid 
  articular 
  face 
  descends 
  to 
  opposite 
  the 
  proximal 
  third 
  of 
  the 
  length; 
  it 
  is 
  trans- 
  

  

  mlVflf 
  versely 
  concave, 
  and 
  its 
  inferior 
  boundary 
  is 
  raised 
  to 
  separate 
  it 
  from 
  the 
  longitudinal 
  concavity 
  

  

  which 
  extends 
  to 
  the 
  head 
  of 
  the 
  bone. 
  A 
  longitudinal 
  angle 
  separates 
  this 
  from 
  the 
  interior 
  

   part 
  of 
  the 
  inferior 
  face. 
  The 
  anterior 
  extremity 
  is 
  curved 
  upwards 
  and 
  is 
  thinned 
  by 
  a 
  strong 
  

   rabbett, 
  which 
  follows 
  the 
  convex 
  margin. 
  This 
  margin 
  is 
  slightly 
  obtuse. 
  The 
  outline 
  is 
  

   abrubtly 
  contracted 
  below 
  the 
  glenoid 
  surface. 
  The 
  inner 
  outline 
  is 
  obtuse, 
  and 
  without 
  trace 
  

   of 
  the 
  intermuscular 
  ridge, 
  on 
  subclavicular 
  ala. 
  The 
  margin 
  expands 
  inwards 
  to 
  the 
  distal 
  

   articular 
  extremity, 
  remaining 
  almost 
  equally 
  obtuse. 
  The 
  distal 
  extremity 
  is 
  far 
  less 
  expanded 
  

   towards 
  the 
  median 
  line 
  of 
  the 
  sternum 
  than 
  in 
  Sula 
  bassana. 
  It 
  is 
  also 
  everted, 
  the 
  outer 
  

   (inferior) 
  projecting 
  border, 
  being 
  turned 
  out 
  (down) 
  from 
  the 
  line 
  of 
  the 
  shaft. 
  In 
  Sula 
  bas- 
  

   sana 
  this 
  marginal 
  rim 
  appears, 
  from 
  Edwards' 
  plate, 
  to 
  be 
  in 
  the 
  plane 
  of 
  the 
  shaft. 
  The 
  articular 
  sur- 
  

   face 
  is 
  divided 
  by 
  this 
  rim 
  into 
  a 
  narrow 
  marginal 
  external 
  (inferior) 
  and 
  a 
  very 
  much 
  wider, 
  strongly 
  concave 
  inner 
  

   portion. 
  The 
  latter 
  is 
  wider 
  at 
  the 
  median 
  end, 
  where 
  its 
  inner 
  (superior) 
  margin 
  is 
  very 
  convex 
  ; 
  it 
  then 
  contracts 
  

   abruptly, 
  leaving 
  the 
  remaining 
  portion 
  only 
  one-half 
  as 
  wide. 
  The 
  very 
  slight 
  prominence 
  of 
  the 
  dividing 
  angulate 
  

   projecting 
  margin, 
  distinguishes 
  this 
  genus 
  from 
  Sula 
  bassana. 
  

  

  There 
  are 
  three 
  pneumatic 
  foramina 
  of 
  no 
  great 
  size, 
  in 
  a 
  short 
  series 
  commencing 
  just 
  within 
  the 
  head 
  of 
  the 
  

   bone. 
  I 
  am 
  only 
  able 
  to 
  compare 
  this 
  bone 
  with 
  the 
  figure 
  of 
  the 
  same 
  element 
  of 
  the 
  Sida 
  bassana 
  given 
  by 
  Edwards, 
  

   as 
  our 
  museum 
  does 
  not 
  possess 
  a 
  skeleton 
  referable 
  to 
  this 
  genus. 
  

  

  As 
  compared 
  with 
  the 
  above, 
  the 
  glenoid 
  articular 
  face 
  descends 
  more 
  posteriorly 
  (lower), 
  and 
  the 
  superior 
  

   (proximal) 
  margin 
  is 
  more 
  transverse. 
  The 
  shaft 
  viewed 
  from 
  before 
  (below), 
  contracts 
  gradually 
  towards 
  the 
  distal 
  

   expansion. 
  The 
  same 
  contraction 
  is 
  visible 
  when 
  viewed 
  from 
  the 
  inner 
  side. 
  On 
  the 
  same 
  view 
  we 
  observe 
  that 
  the 
  

   clavicular 
  articulation 
  is 
  rather 
  more 
  posterior 
  (lower 
  down), 
  and 
  the 
  distal 
  articular 
  marginal 
  edge 
  is 
  far 
  less 
  promi- 
  

   nent 
  and 
  acute. 
  The 
  inferior 
  (outer) 
  narrow 
  articular 
  margin 
  is 
  much 
  narrower 
  than 
  in 
  S. 
  bassana. 
  

  

  Inches. 
  

  

  Length 
  to 
  inner 
  distal 
  angle, 
  3 
  -02 
  

  

  " 
  " 
  posterior 
  basis 
  of 
  scapular 
  articulation, 
  .18 
  

  

  Width 
  of 
  head 
  last 
  point, 
  •57 
  

  

  " 
  " 
  glenoid 
  cavity, 
  -25 
  

  

  " 
  shaft, 
  - 
  23 
  

  

  " 
  " 
  distal 
  extremity 
  to 
  middle 
  line 
  of 
  shaft 
  produced, 
  .43 
  

  

  Thickness 
  distal 
  extremity, 
  -38 
  

  

  