﻿6G0 
  

  

  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AXD 
  FISHERIES. 
  

  

  [56] 
  

  

  of 
  the 
  gnathopods 
  or 
  peraeopods, 
  and 
  no 
  podobranchiae 
  nor 
  arthrobian- 
  

   chiae 
  on 
  any 
  of 
  the 
  somites, 
  as 
  the 
  following 
  branchial 
  formula 
  shows: 
  

  

  Somites. 
  

  

  Epipotls 
  

  

  Podobranchiso 
  . 
  . 
  . 
  

   Arthrobranchite 
  

   V 
  leurobranchise 
  . 
  

  

  Total. 
  

  

  (1) 
  

   

   

   5 
  

  

  5+(D 
  

  

  Bythocaris 
  nana 
  Smith. 
  

  

  Proc. 
  National 
  Mus., 
  vii, 
  p. 
  499, 
  1885. 
  

  

  (Plate 
  XII, 
  Fig. 
  2.) 
  

  

  Specimens 
  examined. 
  

  

  [Locality 
  : 
  Off 
  Martha's 
  Vineyard.] 
  

  

  This 
  is 
  a 
  small 
  species, 
  at 
  once 
  distinguished 
  from 
  B. 
  Payeri 
  and 
  B. 
  

   gracilis 
  by 
  the 
  very 
  much 
  broader 
  and 
  differently 
  shaped 
  front, 
  and 
  the 
  

   much 
  longer 
  eye-stalks. 
  

  

  The 
  carapax 
  is 
  about 
  three-fourths 
  as 
  broad 
  as 
  its 
  length 
  along 
  the 
  

   dorsum, 
  and 
  the 
  breadth 
  of 
  the 
  front 
  fully 
  a 
  third 
  of 
  the 
  length. 
  The 
  

   supraorbital 
  teeth 
  are 
  very 
  large, 
  and 
  project 
  as 
  far 
  forward 
  as 
  the 
  very 
  

   small 
  rostral 
  tooth. 
  The 
  median 
  carina 
  of 
  the 
  gastric 
  region 
  is 
  low 
  and 
  

   inconspicuous. 
  

  

  The 
  eyes 
  are 
  well 
  developed, 
  placed 
  obliquely 
  upon 
  the 
  stalks, 
  and 
  black. 
  

   The 
  length 
  of 
  the 
  eye 
  and 
  stalk 
  is 
  about 
  equal 
  to 
  the 
  breadth 
  of 
  the 
  

   front, 
  and 
  the 
  diameter 
  of 
  the 
  eye 
  considerably 
  greater 
  than 
  that 
  of 
  the 
  

   stalk, 
  equaling 
  about 
  a 
  fifth 
  the 
  length 
  of 
  the 
  carapax. 
  The 
  first 
  seg- 
  

   ment 
  of 
  the 
  peduncle 
  of 
  the 
  antennula 
  reaches 
  a 
  littlo 
  beyond 
  the 
  eye, 
  

   and 
  its 
  lateral 
  spine 
  is 
  slender 
  and 
  falls 
  considerably 
  short 
  of 
  the 
  dis- 
  

  

  