52 
profundior  quam  in  superiore.  Apertura 
obliqua,  margine  acuto.  Color  epidermidis 
ferrugineus  ;  color  testae  epidermide  pri- 
vatae  albus. 
Long.  3  V2  lin.  ;  lat.  10  x¡7  lin. 
Habitat  cum  precedente. 
Observatio:  Figura  3  specimen  decorti¬ 
cation  ostendit.  Fig.  5  et  6,  specimina  júniora 
exhibent.  Haec  species  Planorbi  corneo  ma¬ 
xime  affinis  at  testa  utrinque  umbilicata  di¬ 
versa." 
D’ORBIGNY,  Voyage  etc. 
“Planorbe  ténagophile,  Planorbis  tenago- 
philus  d’Orb. 
Mollusques  pi.  XLIV,  fig.  9-12. 
P.  corpore  nigrescente. 
Testâ  opacâ,  cornea  vel  castaneâ,  trans- 
versim  striatâ,  superne  plano-concavá,  sub- 
carinatâ,  subtus  concavâ,  carinatá,  su¬ 
tura  angulosa,  profundâ;  aperturâ  obliquá 
semilunari.  Diam.  16  millim.  ;  ait.  8  millim. 
Nous  devons  supposer  qu’elle  habite 
toutes  les  plaines  de  l’Amérique  méridionale 
depuis  Corrientes  jusqu’en  Bolivia.  Dans  ce 
dernier  lieu,  elle  est  toujours  plus  petite, 
tandis  qu’à  Santa  Cruz  elle  est  souvent 
beaucoup  plus  déprimeé’’. 
4.  Planorbis  guadaloupensis  SOWERBY. 
(Plate  17,  fig.  7.  a,  b,  c,  d.) 
This  species  was  taken  among  aquatic 
plants  in  the  Lagoa  de  Estremoz  near  Natal, 
where  it  was  rather  scarce.  1  also  received 
living  specimens  from  Maranhão,  sent  by  Mr. 
FABRICIO  CALDAS  DE  OLIVEIRA.  BAKER 
had  already  found  empty  shells  in  the  la¬ 
kes  of  Estremoz  and  Papary.  It  seems  fre¬ 
quent  in  Venezuela,  where  it  was  determi¬ 
ned  by  V.  MARTENS  (1)  and  figured  in  a 
paper  of  ITURBE  and  GONÇALES,  who 
consider  it  as  the  principal  intermediary  host  of 
Schistosomum  mansoni.  In  the  Antilles  it 
seems  to  exist  not  only  at  Guadaloupe 
from  where  it  took  its  name,  but  also  in 
other  islands,  as  for  instance  Portorico. 
1)  This  author  cite9  also  Nova  Granada,  Cayenne 
and  Surinam. 
Our  specimens  agree  perfectly  with  the 
drawing  of  SOWERBY  and  the  phototypy  of 
the  venezuelian  authors.  With  a  width  of 
about  18  mm.  (2)  and  a  height  of  about  5  mm., 
it  is  much  larger  tham  centimetralis ,  but  much 
smaller  than  oliváceas.  It  has  5  V2  high  and 
rather  narrow  whorls,  kidney-shaped  in 
section  and  with  somewhat  blunt  superior 
keel.  The  shell  is  generally  clean  and  po¬ 
lished,  very  transparent  Lut  somewhat  yel¬ 
lowish  ;  it  contains  a  very  black  animal  with 
plenty  of  red  blood’;  it  has  a  great  at¬ 
traction  for  the  miracidia  of  Schistosomum 
and  is  easily  infected  by  the  antennae,  as 
verified  by  me  in  specimens  from  Maranhão. 
In  REEVE-SOWERBY,  Monograph  of 
the  Genus  Planorbis  the  following  description 
is  found  : 
“PLANORBIS  GUADALOUPENSIS. 
Testâ  sinistrali,  compressâ,  lata,  fulvâ,  poli- 
tâ  ;  spirâ  concavâ,  anfractibus  senis,  conve- 
xiusculis  ;  ultimo  anfractu  magno,  supra  su¬ 
turam  elevatâ,  turn  declivi,  infra  latiusculâ  ; 
disco  inferior!  convexo,  aperturâ  subtriagoná 
inferiori  ad  anfractum  productâ. 
SOWERBY,  Genera  of  Recent  and  Fos¬ 
sil  Shells. 
Hab.  Guadaloupe.’’ 
5.  Planorbis  centimetralis  n.  sp. 
(Plate  XVII  fig.  8,  a,  b,  c,  d.) 
In  the  State  of  Pernambuco,  one  of  the 
principal  centres  of  intestinal  schistosoma- 
tosis,  the  largest  species  of  Planorbis  are 
unknown,  but  a  smaller  one  is  widely  spread, 
as  well  in  rivers  as  in  ponds.  Trying  to  de¬ 
termine  it,  I  found  considerable  difficulty.  It 
looks  somewhat  like  peregrinus  D’ORB.  of 
which  F.  BAKER  mentions  a  specimen  from 
Ceará  which  may  belong  to  our  species  ; 
the  true  peregrinus ,  however,  which  1  obtained 
in  Montevideo,  is  larger  and  differs  by  the 
form  of  the  last  whorl.  BAKER  also  mentions 
stra mineas  DUNKER  as  a  species  of  Ceará, 
but  its  size  and  form  do  not  agree,  if  the 
drawing  of  REEVE-SOWERBY  be  correct. 
2)  Von  Martens  mentions  specimens  of  24  mm.  (Ve¬ 
nezuela  and  Surinam). 
