﻿584 
  BEPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  [96] 
  

  

  EXPLANATION 
  OF 
  PLATE 
  XX. 
  

  

  Clupea 
  sapidissima. 
  (The 
  Common 
  Shad.) 
  

  

  FlG. 
  142. 
  Cartilaginous 
  cranium 
  of 
  the 
  larval 
  shad 
  on 
  the 
  sixth 
  day 
  after 
  hatching. 
  

   Au 
  auditory 
  capsule, 
  Mm 
  hyomandibular, 
  Ch' 
  ceratohyal, 
  Gh 
  glossohyal, 
  Mk 
  

   Meckel's 
  cartilage, 
  Ih 
  interhyal, 
  Tr 
  cranial 
  trabecula, 
  Ao 
  antorbital 
  process, 
  B 
  ros- 
  

   trum, 
  i, 
  ii, 
  iii, 
  iv, 
  v, 
  branchial 
  arches 
  ; 
  To 
  tegmen 
  cranii, 
  Sy 
  symplectic, 
  Bp 
  basip- 
  

   terygial 
  plate 
  from 
  which 
  the 
  actinosts 
  are 
  developed, 
  So 
  coraco-scapular 
  plate 
  

   perforated 
  by 
  a 
  foramen. 
  

  

  Fig. 
  143. 
  Cartilaginous 
  cranium 
  of 
  a 
  young 
  shad 
  shortly 
  after 
  hatching. 
  Lettering 
  

   as 
  before, 
  except 
  Ch, 
  which 
  in 
  this 
  figure 
  indicates 
  the 
  chorda 
  ; 
  Q 
  the 
  quadrate, 
  a 
  

   continuation 
  of 
  the 
  hyomandibular. 
  

  

  Fig. 
  144. 
  Mesial 
  section 
  through 
  the 
  head 
  of 
  a 
  young 
  shad 
  shortly 
  after 
  hatching. 
  

   mo 
  medulla 
  oblongata, 
  Co 
  cerebellum, 
  mb 
  mid-brain, 
  Pn 
  pineal 
  body, 
  Cer 
  cer- 
  

   ebrum, 
  Inf 
  infundibulum, 
  Hy 
  hypophysis, 
  bb 
  basibranchial, 
  Ch' 
  basihyal, 
  Gh 
  glos- 
  

   sohyal, 
  Tr 
  anterior 
  prolongation 
  of 
  the 
  trabecules 
  as 
  the 
  rostral 
  plate, 
  M 
  k 
  Meckel's 
  

   cartilage, 
  i, 
  ii, 
  iii, 
  iv, 
  v, 
  the 
  open 
  lumina 
  of 
  the 
  branchial 
  clefts, 
  MM 
  M 
  an- 
  

   terior 
  myotomes, 
  ba 
  bulbus 
  aortas, 
  ve 
  ventricle, 
  sv 
  sinus 
  venosus, 
  po 
  pericardia 
  

   cavity, 
  Y 
  yelk, 
  p 
  periblast, 
  so 
  cleavage 
  cavity. 
  

  

  