﻿338 
  Mr. 
  A. 
  J. 
  Jukes-Browne 
  on 
  

  

  XXXV^II. 
  — 
  Description 
  of 
  a 
  7iew 
  Ci/prinodont 
  Fish 
  of 
  the 
  

   Genus 
  MoUienisia/rom 
  Yucatan. 
  By 
  0. 
  Tate 
  Regan, 
  M.A. 
  

  

  (Published 
  by 
  permission 
  of 
  the 
  Trustees 
  of 
  the 
  British 
  Museum.) 
  

  

  Mollienisia 
  velifera, 
  sp. 
  n. 
  

  

  Deptli 
  of 
  body 
  2^ 
  to 
  3 
  in 
  the 
  leng-th, 
  lengfli 
  of 
  head 
  3^ 
  to 
  

   3i. 
  Diameter 
  of 
  eye 
  3^ 
  in 
  the 
  length 
  of 
  head, 
  interorbifcal 
  

   width 
  2. 
  27 
  scales 
  in 
  a 
  longitudinal 
  series. 
  Dorsal 
  18-19 
  ; 
  

   base 
  a 
  little 
  longer 
  than 
  distance 
  from 
  end 
  of 
  snout 
  (?) 
  or 
  

   1| 
  to 
  twice 
  tiiat 
  distance 
  ( 
  c? 
  ) 
  ; 
  longest 
  rays 
  | 
  (?) 
  or 
  If 
  

   to 
  2 
  ( 
  c^ 
  ) 
  as 
  long 
  as 
  head. 
  Anal 
  10. 
  Pectoral 
  as 
  long 
  as 
  

   head 
  ; 
  pelvics 
  reaching 
  origin 
  of 
  anal 
  (?) 
  or 
  with 
  the 
  second 
  

   ray 
  produced 
  and 
  as 
  long 
  as 
  the 
  introraittent 
  organ 
  {c^). 
  

   Caudal 
  rounded 
  (?) 
  or 
  with 
  the 
  lower 
  angle 
  somewhat 
  

   produced 
  (cJ). 
  Least 
  depth 
  of 
  caudal 
  peduncle 
  a 
  little 
  less 
  

   than 
  length 
  of 
  head. 
  Olivaceous 
  ; 
  3 
  or 
  4 
  dark 
  bars 
  almost 
  

   covered 
  by 
  the 
  pectoral 
  fins 
  ; 
  back 
  and 
  sides 
  with 
  dark 
  brown 
  

   longitudinal 
  stripes, 
  broader 
  ones 
  along 
  and 
  narrower 
  ones 
  

   between 
  the 
  series 
  of 
  scales 
  ; 
  series 
  of 
  pearl-like 
  white 
  spots 
  

   between 
  the 
  stripes, 
  2 
  spots 
  on 
  each 
  scale 
  ; 
  these 
  markings 
  

   much 
  more 
  conspicuous 
  in 
  the 
  male. 
  Dorsal 
  fin 
  dark, 
  with 
  

   numerous 
  pale 
  spots 
  ; 
  in 
  males 
  a 
  series 
  of 
  more 
  or 
  less 
  

   distinct 
  large 
  dark 
  spots 
  in 
  the 
  distal 
  part 
  of 
  the 
  fin 
  ; 
  caudal 
  

   nearly 
  immaculate 
  (?) 
  or 
  the 
  upper 
  | 
  with 
  dark 
  and 
  pale 
  

   spots 
  and 
  the 
  lower 
  ^ 
  plain, 
  black-edged 
  (c?). 
  

  

  Progreso, 
  Yucatan. 
  

  

  Two 
  males 
  (80 
  and 
  105 
  mm.) 
  anl 
  a 
  female 
  (92 
  mm.) 
  

   presented 
  to 
  the 
  British 
  Museum 
  by 
  Herr 
  J. 
  Paul 
  Arnold. 
  

  

  This 
  beautiful 
  new 
  fish 
  is 
  related 
  to 
  M.petenensis, 
  but 
  differs 
  

   in 
  the 
  larger 
  head, 
  fewer 
  scales, 
  coloration, 
  &c., 
  but 
  especially 
  

   in 
  the 
  larger 
  dorsal 
  fin, 
  which 
  has 
  more 
  rays 
  than 
  in 
  any 
  

   other 
  species 
  of 
  the 
  genus, 
  M. 
  petenends 
  and 
  M. 
  latipinna, 
  

   which 
  come 
  next 
  to 
  it, 
  having 
  11 
  to 
  IG. 
  

  

  XXXVIIl. 
  — 
  Note 
  on 
  dementia 
  subdiaphana, 
  Carp. 
  

   By 
  A. 
  J. 
  Jukes-Browne, 
  F.R.S., 
  F.G.S. 
  

  

  I 
  DESIRE 
  to 
  make 
  a 
  correction 
  respecting 
  the 
  shell 
  which 
  

   was 
  described 
  as 
  a 
  new 
  species 
  of 
  dementia 
  in 
  this 
  magazine 
  

   for 
  July 
  1913. 
  Dr. 
  Dall, 
  of 
  the 
  U.S. 
  National 
  Museum, 
  

   has 
  since 
  identified 
  it 
  as 
  the 
  adult 
  form 
  of 
  the 
  shell 
  which 
  

   was 
  described 
  by 
  Ph. 
  Carpenter 
  in 
  18G5 
  under 
  the 
  name 
  of 
  

   dementia 
  subiUnphana 
  . 
  

  

  