﻿270 
  On 
  a 
  new 
  Gemts 
  of 
  Parasitic 
  Mollusca. 
  

  

  XX 
  VII. 
  — 
  Description 
  of 
  a 
  new 
  Genus 
  of 
  Parasitic 
  Mollusca. 
  

   By 
  Edgar 
  A. 
  Smith. 
  

  

  About 
  a 
  year 
  ago 
  the 
  British 
  Museum 
  purchased 
  of 
  Mr. 
  

   Robillard, 
  of 
  the 
  Mauritius, 
  among 
  other 
  specimens, 
  a 
  single 
  

   example 
  of 
  a 
  shell, 
  which, 
  according 
  to 
  his 
  statement, 
  appears 
  

   to 
  have 
  been 
  u 
  found 
  living 
  on 
  an 
  Echinus." 
  This 
  specimen 
  

   I 
  have 
  been 
  unable 
  to 
  locate 
  in 
  any 
  known 
  genus 
  of 
  parasitic 
  

   Mollusca. 
  

  

  The 
  number 
  of 
  genera 
  which 
  may 
  be 
  truly 
  said 
  to 
  be 
  para- 
  

   sitic 
  appears 
  to 
  be 
  very 
  small. 
  

  

  Stilifer 
  lives 
  a 
  parasite 
  upon 
  Echini 
  or 
  in 
  the 
  skin 
  or 
  tegu- 
  

   ment 
  of 
  starfishes. 
  Some 
  species 
  of 
  Eulima 
  are 
  found 
  in 
  

   Holothurians, 
  the 
  abode 
  also 
  of 
  the 
  curious 
  Entoconclia. 
  Sty- 
  

   liferina 
  occurs 
  on 
  species 
  of 
  Ophiurida?. 
  

  

  Stimpson 
  has 
  named 
  a 
  parasitic 
  mollusk 
  Cochliolepis 
  para- 
  

   siticus 
  which 
  lives 
  beneath 
  the 
  scales 
  of 
  an 
  Annelid 
  (Acoeles 
  

   hipina). 
  Many 
  species 
  of 
  Ovula 
  are 
  found 
  only 
  upon 
  Gor- 
  

   gonice 
  ; 
  Capuhis 
  crystallinus 
  infests 
  the 
  rays 
  of 
  starfish 
  ; 
  one 
  

   or 
  two 
  species 
  of 
  Odostomia 
  are 
  said 
  to 
  occur 
  on 
  Pecten 
  ; 
  the 
  

   little 
  Pedicularia 
  lives 
  parasitic 
  upon 
  corals 
  &c. 
  ; 
  and 
  the 
  

   species 
  of 
  Bhizochilus, 
  Coralliophila, 
  Cryptobia, 
  Leptoconcha, 
  

   and 
  Magilus 
  are 
  invariably 
  found 
  in 
  or 
  upon 
  corals, 
  but 
  to 
  

   what 
  extent 
  they 
  may 
  be 
  regarded 
  as 
  truly 
  parasitic 
  has 
  not 
  

   as 
  yet 
  been 
  determined. 
  The 
  female 
  of 
  Lamellaria 
  perspicua 
  

   is 
  said 
  to 
  deposit 
  its 
  eggs 
  in 
  a 
  compound 
  Ascidian 
  (Lepto- 
  

   clinum). 
  A 
  i'ew 
  species 
  of 
  bivalves 
  are 
  known 
  to 
  be 
  parasitic. 
  

   Leplon 
  parasiticum, 
  Dall, 
  lives 
  upon 
  a 
  sea-urchin 
  [llemiaster 
  

   cavernosus) 
  . 
  A 
  species 
  of 
  Montacuta 
  is 
  " 
  invariably 
  found 
  

   attached 
  to 
  the 
  spines 
  of 
  Spatangus 
  purpureus 
  and 
  other 
  

   Eehinoderms 
  of 
  the 
  same 
  kind." 
  Modiolaria 
  marmorata 
  

   burrows 
  into 
  the 
  test 
  of 
  Ascidians, 
  and 
  the 
  genera 
  Vulsella 
  

   and 
  Crenatula 
  live 
  in 
  sponges. 
  Pedum 
  and 
  Tridacna 
  and 
  

   some 
  species 
  of 
  Lithodomus 
  occur 
  in 
  corals 
  ; 
  but 
  these 
  can 
  

   scarcely 
  be 
  considered 
  parasitic 
  forms. 
  The 
  glochidium-stage 
  

   of 
  Anodonta 
  is 
  truly 
  parasitic, 
  obtaining 
  nourishment 
  from 
  

   the 
  fish 
  to 
  which 
  it 
  has 
  become 
  attached. 
  

  

  The 
  species 
  under 
  consideration 
  bears 
  only 
  a 
  general 
  

   resemblance 
  in 
  form 
  to 
  one 
  of 
  those 
  which 
  I 
  have 
  mentioned, 
  

   namely 
  Cochliolepis 
  parasiticus 
  *. 
  As 
  its 
  conditions 
  of 
  life 
  

   are 
  so 
  different, 
  there 
  is 
  little 
  doubt 
  but 
  that 
  it 
  is 
  generically 
  

   quite 
  distinct, 
  and 
  I 
  therefore 
  propose 
  to 
  describe 
  it 
  as 
  such 
  

   under 
  the 
  name 
  Rohillardia. 
  Its 
  systematic 
  position 
  is 
  

  

  * 
  Stimpson, 
  Proc. 
  Bost. 
  Soc. 
  Nat. 
  Hist. 
  1888, 
  vol. 
  vi. 
  p. 
  308, 
  woodcut. 
  

  

  