﻿180 
  ACTINOPTEETGII. 
  

  

  considerably 
  less 
  than 
  one 
  half 
  the 
  maximum 
  depth 
  of 
  the 
  abdo- 
  

   minal 
  region. 
  Vertebral 
  rings 
  well 
  ossified. 
  Dorsal 
  fin 
  arising 
  

   opposite 
  the 
  fourth 
  or 
  fifth 
  vertebra, 
  with 
  about 
  26 
  rays, 
  which 
  are 
  

   not 
  expanded, 
  but 
  bifurcate 
  distally 
  at 
  least 
  in 
  its 
  hinder 
  half. 
  

   Pelvic 
  fins 
  arising 
  midway 
  between 
  the 
  pectoral 
  and 
  caudal 
  fins, 
  

   and 
  the 
  anal, 
  with 
  6 
  or 
  7 
  rays, 
  shortly 
  behind. 
  Squamation 
  very 
  

   thin. 
  

  

  Form. 
  Sf 
  Loc. 
  Portlandian 
  : 
  Meuse, 
  France. 
  

  

  P. 
  7359. 
  Counterpart 
  of 
  type 
  specimen 
  ; 
  Upper 
  Portlandian 
  (" 
  La 
  

   Garde 
  "), 
  Savonnieres 
  -en-Perthois, 
  Meuse. 
  The 
  vertebral 
  

   rings 
  are 
  shown 
  to 
  be 
  complete 
  and 
  well 
  ossified, 
  and 
  the 
  

   neural 
  arches 
  throughout 
  the 
  trunk, 
  the 
  haemal 
  arches 
  

   in 
  the 
  caudal 
  region, 
  besides 
  all 
  the 
  fin-supports, 
  are 
  

   especially 
  robust. 
  The 
  present 
  writer 
  cannot 
  distinguish 
  

   more 
  than 
  26 
  dorsal 
  and 
  7 
  anal 
  fin-rays. 
  The 
  hinder- 
  

   most 
  dorsal 
  rays 
  are 
  clearly 
  proved 
  to 
  bifurcate. 
  Traces 
  

   of 
  the 
  extremely 
  delicate 
  flank-scales 
  occur 
  above 
  the 
  

   pelvic 
  fins. 
  Purchased, 
  1894. 
  

  

  Macrosemius 
  andrewsi, 
  A. 
  S. 
  Woodward. 
  

  

  1895. 
  Macrosemius 
  andrewsi, 
  A. 
  S. 
  Woodward, 
  Geol. 
  Mag. 
  [4] 
  vol. 
  ii. 
  

   p. 
  148, 
  pi. 
  vii. 
  fig. 
  3. 
  

  

  Type. 
  Nearly 
  complete 
  fish 
  ; 
  British 
  Museum. 
  

  

  A 
  very 
  small 
  species, 
  about 
  0*035 
  in 
  length, 
  closely 
  similar 
  to 
  the 
  

   preceding 
  but 
  with 
  relatively 
  stouter 
  caudal 
  region. 
  Separate 
  

   hypocentra 
  and 
  pleurocentra 
  in 
  notochordal 
  sheath. 
  Dorsal 
  fin 
  

   with 
  about 
  25 
  slender 
  rays, 
  arising 
  above 
  the 
  fifth 
  pair 
  of 
  ribs. 
  

   Pelvic 
  fins 
  arising 
  about 
  midway 
  between 
  the 
  pectoral 
  and 
  caudal 
  

   fins, 
  and 
  the 
  anal, 
  with 
  7 
  or 
  8 
  rays, 
  shortly 
  behind. 
  Squamation 
  

   very 
  thin. 
  

  

  Form. 
  <5f 
  Loc. 
  Purbeckian 
  : 
  Wiltshire. 
  

  

  P. 
  6303. 
  The 
  type 
  specimen, 
  in 
  counterpart, 
  described 
  and 
  figured 
  

   loc. 
  cit. 
  ; 
  Middle 
  Purbeck, 
  Teffont. 
  

  

  Presented 
  by 
  Rev. 
  W. 
  B. 
  Andrews, 
  1890. 
  

  

  The 
  following 
  specimens 
  may 
  perhaps 
  indicate 
  a 
  species 
  of 
  Macro- 
  

   semius 
  from 
  the 
  Stonesfield 
  Slate, 
  while 
  two 
  premaxillse 
  and 
  a 
  

   maxilla 
  figured 
  by 
  J. 
  Phillips 
  (Geol. 
  Oxford, 
  1871, 
  p. 
  180, 
  woodc. 
  xl. 
  

   figs. 
  8, 
  9) 
  may 
  pertain 
  to 
  the 
  same 
  fish 
  ; 
  these 
  specimens, 
  however, 
  

   are 
  insufficient 
  for 
  determination. 
  

  

  P. 
  3617. 
  Dentigerous 
  bone, 
  probably 
  maxilla, 
  named 
  Macrosemius 
  

   brevirostris 
  by 
  Agassiz 
  (Poiss. 
  Foss. 
  vol. 
  ii. 
  pt. 
  ii. 
  1844, 
  

  

  