304 
PBOF.  T.  B.  JONES  ON  PALAEOZOIC  OSTBACODA  [Allg.  1 8 93, 
2.  Ulbichia  gibvanensis,  sp.  nov.  (PI.  XIY.  fig.  8.) 
Size. — Length  *7 2,  height  *48  millim. 
Fig.  8  seems  to  he  decidedly  a  bituberculate  valve,  without  the 
normal  Beyriehian  features,  although  the  posterior  moiety  of  the 
valve  hears  a  slight  eminence.  It  is  neatly  sub-oblong,  straight  on 
the  upper,  elliptically  curved  on  the  lower  edge,  and  almost  symme¬ 
trically  rounded  at  the  ends.  The  pair  of  tubercles  are  high  up  in 
the  medio-dorsal  region,  and  the  smaller  of  the  two  is  rather  in  front 
of  the  other. 
This  species  may  be  known  conveniently  as  girvanensis.  Fig.  8  is 
in  no.  123,  grey  shale. 
“ Primitia  perforata Barrande,  ‘  Syst.  Sil.  Boheme,’  vol.  i.  Suppl. 
1872,  p.  550,  pi.  xxvii.  fig.  12,  is  a  somewhat  similar  Vlrichia ,  hut 
more  oval  and  with  a  small,  deep,  pit-like  sulcus  between  two  round 
unequal  tubercles. 
3.  Ulbichia  Gbay.e,  sp.  nov.  (PI.  XIY.  fig.  9.) 
Size. — Length  2'08,  height  1*36  millim. 
This  is  evidently  a  large,  well-pronounced  Vlrichia ,  with  a  bean¬ 
shaped  and  somewhat  reniform  outline,  larger  behind  than  in  front, 
with  well-defined  dorsal  angles,  a  deep,  straight  sulcus,  and  two 
strong  tubercles,  both  broken,  one  (anterior)  leaving  a  broader 
fracture  than  the  other.  The  specimen,  being  an  internal  cast,  fails 
to  show  the  surface  of  the  valve. 
The  definite  features  and  large  size  make  it  worthy  of  a  specific 
distinction  under  the  name  Vlrichia  Grayer;,  by  which  we  can 
recognize  the  assiduous  and  intelligent  care  exercised  by  the  ener¬ 
getic  collector  of  these  and  numerous  other  fossils  at  Girvan. 
The  specimen  occurs  with  the  cast  of  a  small  Beyrichia  Kloecleni  (?) 
in  greenish-grey,  finely  micaceous  shale,  from  Bargany-Pond  Burn, 
and  is  regarded  as  belonging  to  the  Llandovery  formation. 
Y.  Genus  Sulcuna,  Jones  &  Kirkby,  1874. 
1.  Sulcuna  pbh:cubbens,  sp.  nov.  (Pl.  XIY.  figs.  10,  11.)  * 
Size. — Fig.  10  ;  . Length  *8,  height  ’6  millim. 
[  without  the  margin,  length  1*16,  height  *8  millim. 
lo'  [with  the  margin,  length  L32,  height  ‘92  millim. 
PI.  XIY.  fig.  10,  has  a  striking  resemblance  to  some  Carboniferous 
forms  of  Sulcuna  figured  and  described  in  the  Monogr.  Carbonif. 
Cypridin.,  Pal.  Soc.  Part  I.  1874,  pp.  36,  37  ;  and  at  the  same  time 
there  is  an  apparent  relationship  to  PI.  XIY.  fig.  1  (Girvan,  see  above, 
p.  300),  except  that  in  figs.  10  and  11  the  Primitian  sulcus  is  empty, 
leaving  the  dorsal  margin  hare  and  deeply  notched.  In  these 
poorly  preserved  casts  we  have  not  sufficiently  clear  evidence  to  be 
certain  on  all  points,  either  of  detail  or  generalization. 
Fig.  11,  although  of  relatively  large  size,  and  apparently  cha¬ 
racterized  by  sulcus  and  border,  is  only  a  hollow  cast,  not  quite 
