﻿SKELETON. 
  41 
  

  

  when 
  quite 
  young 
  these 
  Batrachians 
  present 
  a 
  con- 
  

   dition 
  similar 
  to 
  that 
  which 
  persists 
  throughout 
  life 
  in 
  

   the 
  other 
  families. 
  

  

  A 
  cartilage 
  in 
  the 
  median 
  line 
  in 
  front, 
  supported 
  

   by 
  a 
  bony 
  style 
  in 
  Bana, 
  is 
  the 
  so-called 
  omosternum 
  ; 
  

   a 
  larger 
  one 
  behind 
  is 
  the 
  sternum. 
  This 
  is 
  also 
  

   provided 
  with 
  a 
  bony 
  style 
  in 
  Bana, 
  Peloclytes, 
  and 
  

   Pelohates 
  ; 
  or 
  a 
  portion 
  of 
  it 
  may 
  be 
  calcified, 
  as 
  in 
  

   Hyla 
  and 
  Bufo. 
  In 
  the 
  Discoglossidse 
  the 
  sternum 
  is 
  

   produced 
  into 
  two 
  posteriorly 
  diverging 
  cartilaginous 
  

   or 
  calcified 
  styles. 
  

  

  The 
  shoulder-blade 
  is 
  divided 
  into 
  two 
  parts, 
  the 
  

   ossified 
  scapula 
  proper 
  and 
  the 
  supra-scapula, 
  carti- 
  

   laginous 
  or 
  incompletely 
  ossified, 
  bent 
  over 
  at 
  an 
  angle 
  

   to 
  the 
  scapula. 
  

  

  The 
  prsecoracoid 
  enters 
  the 
  glenoid 
  cavity 
  in 
  the 
  

   Discoglossidce, 
  Bufoniddd, 
  and 
  Hylidse, 
  but 
  not 
  in 
  the 
  

   three 
  other 
  families, 
  where 
  the 
  cavity 
  is 
  formed 
  by 
  

   the 
  scapula 
  and 
  coracoid. 
  

  

  The 
  humerus 
  is 
  a 
  feebly 
  curved 
  bone 
  with 
  a 
  globular 
  

   distal 
  condyle 
  and 
  a 
  strong 
  prgeaxial 
  crest, 
  which 
  is 
  

   more 
  developed 
  in 
  males 
  than 
  in 
  females, 
  and 
  which 
  

   in 
  the 
  former 
  may 
  be 
  supplemented 
  by 
  a 
  second 
  crest 
  

   lower 
  down. 
  The 
  head 
  is 
  replaced 
  by 
  an 
  epiphysis, 
  

   which 
  calcifies 
  late, 
  or 
  never 
  as 
  in 
  the 
  Discoglossidse 
  and 
  

   Pelohatidde. 
  The 
  radius 
  and 
  ulna 
  are 
  fused 
  to 
  a 
  single 
  

   bone, 
  which 
  is 
  shorter 
  than 
  the 
  humerus. 
  The 
  ulnar 
  

   part 
  projects 
  beyond 
  the 
  radius 
  at 
  the 
  articulation 
  

   with 
  the 
  humerus. 
  

  

  The 
  carpal 
  bones 
  vary 
  from 
  six 
  to 
  eight. 
  In 
  the 
  

   more 
  primitive 
  carpus, 
  such 
  as 
  is 
  represented 
  by 
  the 
  

   Discoglossidse 
  (Fig. 
  17, 
  a), 
  we 
  find, 
  following 
  the 
  

   nomenclature 
  of 
  Howes 
  and 
  Ridewood, 
  two 
  elements 
  

   in 
  contact 
  with 
  the 
  radius-ulna, 
  the 
  radiale 
  and 
  ulnare 
  ; 
  

   two, 
  regarded 
  as 
  centralia, 
  in 
  the 
  second 
  row; 
  and 
  

   four, 
  plus 
  a 
  vestigial 
  ligamentous 
  fifth, 
  in 
  the 
  third 
  

   row. 
  The 
  fourth 
  distal 
  carpale 
  may 
  fuse 
  with 
  the 
  

   outer 
  centrale, 
  as 
  in 
  Pelodytes 
  (b), 
  or 
  also 
  with 
  the 
  

   third 
  distal 
  element, 
  as 
  in 
  Bufo, 
  Hyla, 
  and 
  Bana 
  (o). 
  

  

  