﻿AND 
  AYES 
  OF 
  NORTH 
  AMERICA. 
  

  

  SYNOPSIS 
  OF 
  THE 
  PRIMARY 
  TYPES 
  EMBRACED 
  IN 
  THIS 
  ESSAY 
  

  

  The 
  Classes 
  Aves, 
  Reptilia, 
  and 
  Batrachia 
  are 
  those 
  over 
  which 
  the 
  present 
  review 
  

   extends. 
  The 
  classes 
  of 
  veretebrata 
  not 
  included 
  are 
  : 
  the 
  Dipnoi, 
  Pisces, 
  Elasmobranchi, 
  

   Dermopteri, 
  and 
  Leptocardii 
  and 
  the 
  Mammalia. 
  

  

  The 
  Aves, 
  Reptilia, 
  and 
  Batrachia 
  are 
  characterized 
  and 
  distinguished 
  from 
  all 
  the 
  

   other 
  classes 
  as 
  follows 
  : 
  the 
  points 
  wherein 
  they 
  differ 
  from 
  each 
  other 
  are 
  italicized. 
  

  

  BATRACHIA. 
  

  

  Axial 
  element 
  of 
  the 
  brain 
  chamber 
  a 
  single 
  membrane 
  bone, 
  the 
  para-sphenoid 
  ; 
  occipital 
  

  

  condyles 
  two, 
  on 
  the 
  exoccipitals. 
  

   Mandible 
  compound, 
  supported 
  by 
  quadratum. 
  

   A 
  distinct 
  coracoid 
  bone. 
  

   Limbs 
  when 
  present 
  ambulatory, 
  attached 
  anteriorly 
  to 
  a 
  scapular 
  arch 
  which 
  is 
  free 
  from 
  

  

  the 
  cranium. 
  

   Nervous 
  System. 
  Cerebral 
  hemispheres 
  larger 
  than 
  optic 
  lobes, 
  not 
  covering 
  the 
  optic 
  

  

  thalami, 
  and 
  with 
  the 
  lateral 
  ventricle 
  on 
  their 
  inner 
  side. 
  

   Fornix 
  and 
  arbor 
  vitee 
  none; 
  medulla 
  oblongata 
  straight 
  ; 
  olfactory 
  lobes 
  terminal, 
  sessile. 
  

   Circulatory 
  /System. 
  Heart 
  with 
  two 
  and 
  three 
  chambers. 
  

   Three 
  or 
  more 
  aorta 
  bows 
  ; 
  aorta 
  with 
  two 
  roots 
  from 
  a 
  ductus 
  communis 
  and 
  bulbus 
  

  

  arteriosus. 
  

  

  REPTILIA. 
  

  

  Axis 
  of 
  brain 
  case, 
  the 
  basi-occipitcd 
  and 
  sphenoid 
  elements 
  developed 
  in 
  the 
  primordial 
  

  

  cartilage, 
  the 
  first 
  with 
  exoccipitals 
  bearing 
  one 
  condyle. 
  

   Mandible 
  compound, 
  supported 
  by 
  quadratum. 
  

   Coracoid 
  bone 
  distinct. 
  

  

  Limbs 
  the 
  anterior 
  attached 
  to 
  a 
  scapular 
  arch 
  which 
  is 
  free 
  from 
  cranium. 
  

   Metatarsals 
  and 
  metacarpals 
  distinct; 
  carpals 
  and 
  second 
  row 
  of 
  tarsals 
  also 
  distinct; 
  

  

  usually 
  the 
  first 
  row 
  of 
  tarsals 
  also. 
  

   Pubis 
  not 
  in 
  contact 
  with 
  ischia 
  distally. 
  

  

  