ANTHEACOPTERA  AND  ANTHRACOMYA. 
271 
Vol.  49.] 
4  Acadian  Geology,’  2nd  ed.  p.  201,  fig.  42 ;  but  I  have  not  been 
able  at  present  to  compare  the  two  forms. 
Locality. — Hard  Mine  Seam,  Dividy  Lane,  North  Staffordshire. 
Anthracomya,  sp.  nov.  (?),  Wheelton  Hind.  (PI.  X.  fig.  23.) 
Specific  Characters. — Shell  oblong,  ovate,  tumid.  Anterior  end  ^ 
of  the  shell,  has  its  superior  border  much  below  the  umbones,  and  is 
bluntly  rounded.  Inferior  border  almost  straight,  joining  the  ante¬ 
rior  and  posterior  borders  with  rounded  angles.  Hiuge-line  straight, 
about  §  length  of  the  shell.  If  it  and  the  inferior  border  were  pro¬ 
duced  anteriorly,  they  would  meet  at  a  very  acute  angle.  IJmbones 
obtusely  broad,  more  conspicuous,  more  elevated  and  separated  than 
usual  with  this  genus,  at  5  distance  of  the  hinge-line  from  the 
anterior  end.  Posterior  border  oblique,  truncate  from  above  down¬ 
wards,  rounded  below.  The  shell  has  a  very  slight  oblique  con¬ 
striction  anteriorly,  more  marked  in  the  left  valve.  There  is  no 
oblique  ridge,  but  the  shell  becomes  generally  swollen,  being  only 
slightly  compressed  towards  the  anterior  end. 
Interior  normal. 
Exterior  (?). 
Size. — Antero-posterior  measurement,  38  mm.  (1|  inch)  ;  dorso- 
ventral,  20  mm.  (1  inch)  ;  lateral,  15  mm.  (-J  inch). 
Remarks. — This  shell  may  possibly  prove  to  be  a  local  variety  of 
A.  mocliolaris,  but  is  distinguished  from  the  typical  form  by  the 
comparative  measurements,  by  the  absence  of  an  oblique  ridge,  and 
by  the  short  hinge-line  and  much  truncated  posterior  border. 
*  Locality. — Durham  Coalfield. 
Anthracomya  Wardi,  Salter  MSS.  (PI.  IX.  figs.  9  &  10.) 
Ward,  Trans.  North  Staffs.  Inst.  Min.  &  Meek.  Eng.  vol.  x.  (1890)  p.  126, 
with  description  by  R.  Etheridge,  F.R.S, 
Specific  Characters. — Shell  small,  oblong,  margins  sub -parallel, 
moderately  convex.  Hinge-line  straight,  nearly  as  long  as  the  shell, 
not  elevated  posteriorly.  Anterior  end  about  |  of  the  shell ;  its 
border  forms  a  right  angle  with  the  hinge-line  above,  bluntly 
rounded  below.  Posterior  end  obliquely  truncate  above,  bluntly 
rounded  at  the  lower  angle,  flattened  above  along  the  hinge-line 
and  backward  into  the  margin.  IJmbones  situated  in  the  ante¬ 
rior  third  of  the  shell.  A  blunt,  oblique  tumidity  extends  from  the 
umbonal  area  towards  the  lower  part  of  the  posterior  end,  where  it 
becomes  lost. 
Exterior. — Surface  smooth,  with  fine,  close,  concentric  striae  and 
lines  of  growth,  rapidly  curving  up  to  the  posterior  hinge-line. 
Periostraeum  thin. 
Size. —  Antero-posterior  measurement,  40  mm.  (1|-  inch);  dorso- 
ventral,  16  mm.  (about  jV  inch).  These  measurements  are,  in  a 
specimen  belonging  to  Mr.  Geo.  Wild,  of  Oldham,  respectively  33  mm. 
(Ill  inch)  and  10  mm.  (§  inch). 
