﻿ACADEMY 
  OF 
  SCIENCES. 
  415 
  

  

  less 
  driven 
  so 
  far 
  south 
  by 
  unusually 
  cold 
  weather. 
  He 
  also 
  stated 
  

   that 
  Mr. 
  Gruber 
  has 
  lately 
  obtained 
  here 
  the 
  first 
  California 
  speci- 
  

   men 
  of 
  the 
  " 
  Arctic 
  Skua," 
  {Stercorarius 
  parasiticus) 
  another 
  evi- 
  

   dence 
  of 
  severe 
  weather 
  approaching. 
  The 
  interior 
  papers, 
  about 
  

   two 
  months 
  since, 
  noticed 
  also 
  the 
  uncommonly 
  early 
  arrival 
  of 
  the 
  

   wild 
  geese 
  from 
  the 
  north. 
  The 
  unusual 
  amount 
  of 
  rain 
  already 
  

   fallen 
  is 
  an 
  evidence 
  of 
  cold 
  weather 
  northward, 
  though 
  we 
  have 
  

   not 
  felt 
  it 
  here, 
  as 
  the 
  upper 
  current 
  of 
  cold 
  north 
  winds 
  condenses 
  

   the 
  moisture 
  brought 
  to 
  us 
  by 
  the 
  warm 
  south 
  winds. 
  These 
  facts 
  

   should 
  be 
  recorded, 
  and 
  we 
  may 
  find 
  the 
  " 
  Foolish 
  " 
  Guillemot 
  

   really 
  a 
  very 
  weatherwise 
  bird. 
  

  

  Description 
  of 
  a 
  New 
  Species 
  of 
  Shell 
  from 
  San 
  Francisco 
  Bay. 
  

  

  BY 
  DR. 
  W. 
  NEWCOMB. 
  

  

  Mya 
  HemphilHi. 
  

  

  Shell, 
  oblong, 
  nearly 
  equivalve, 
  moderately 
  gaping 
  at 
  each 
  extremity, 
  thin, 
  

   opaque 
  or 
  translucent, 
  white, 
  with 
  margin 
  covered 
  with 
  a 
  light 
  yellow 
  epider- 
  

   mis. 
  Yalves, 
  rounded 
  anteriorly, 
  cuneate 
  posteriorly, 
  finely 
  striate 
  transversely 
  

   and 
  longitudinally, 
  near 
  the 
  extremities 
  becoming 
  coarsely 
  striate 
  ; 
  obsoletely 
  

   transversely 
  rayed 
  with 
  an 
  opaque 
  white. 
  Umbones 
  small, 
  depressed, 
  approx- 
  

   imate 
  ; 
  hinge-line, 
  arcuate. 
  Left 
  valve, 
  with 
  a 
  spoon-shaped 
  tooth, 
  posteriorly 
  

   bifid 
  ; 
  right 
  valve, 
  excavated 
  for 
  insertion 
  of 
  the 
  ligament, 
  and 
  furnished 
  with 
  a 
  

   small 
  rudimentary 
  tooth 
  in 
  close 
  apposition 
  with 
  the 
  ligament. 
  

  

  Length, 
  2 
  1-10 
  inch. 
  

  

  Breadth, 
  1 
  3-10 
  inch. 
  

  

  Depth, 
  ^^ 
  inch. 
  

  

  Hab., 
  Bay 
  of 
  San 
  Francisco. 
  

  

  Eemares.— 
  This 
  shell 
  was 
  discovered 
  by 
  H. 
  Hemphill, 
  Esq., 
  to 
  whom 
  the 
  

   scientific 
  world 
  is 
  greatly 
  indebted 
  for 
  his 
  extensive 
  researches 
  on 
  our 
  coast 
  and 
  

   in 
  the 
  interior 
  of 
  our 
  country. 
  The 
  only 
  species 
  with 
  which 
  it 
  can 
  be 
  con- 
  

   founded 
  is 
  the 
  Mya 
  prcecisa 
  of 
  Gould, 
  which 
  Dr. 
  Carpenter 
  considers 
  as 
  identi- 
  

   cal 
  with 
  M. 
  truncata 
  of 
  the 
  Northern 
  Atlantic. 
  

  

  A 
  specimen 
  of 
  31. 
  arenaria, 
  from 
  Puget 
  Sound, 
  in 
  my 
  collection, 
  is 
  quite 
  

   distinct 
  from 
  this 
  species, 
  and, 
  like 
  many 
  of 
  the 
  circumpolar 
  species, 
  is 
  common 
  

   to 
  the 
  North 
  Pacific 
  and 
  North 
  Atlantic, 
  

  

  It 
  is 
  quite 
  distinct 
  from 
  the 
  fossil 
  M. 
  Montereiji, 
  Conrad, 
  as 
  I 
  am 
  informed 
  

   by 
  Dr. 
  Cooper, 
  who 
  kindly 
  made 
  for 
  me 
  the 
  comparison 
  of 
  this 
  shell 
  with 
  

   Conrad's 
  figure 
  and 
  description. 
  

  

  