Smith, Edgar Albert

English

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180  MR. EDGAR A.  SMITH ON  THE MOLLUSCA  [Mal'. 6, October, when sexun,lly mature inc1ivichmls sWH,rmed,  though nOlle showed any tendency to form buds  ~'), Dr. Ounnington's carefully collectell  material, on  the other hand, showed that reproduction by budding was conbinued in August, Septcmber, December,  l1,nd February,  and that it might therefOl'e  l'e>tsonably  be  supposed that it went OIl during the greater part of the year-if, indeed, it ever ceased; The discovery of  Limnoonidc,  in other river-basins  in Africa had materially weakened  the case  of  those  who  considered  tha,t Lake Tanganyika was  the last slll'viving  remllarrt  of  a JUI'assic Sea.  The fact that this Medusa had been  found in the Victol'ift Nyanza  by M.  Oh,  Alluaucl  and  Sir Oharles Eliot,  and  t"lso  in the Niger by  the late Mr. Budgett, proved thn,t it was  another instance  of fl  member of  the freshwflter fauna  chal'l1cteristic  of the Oentral-African Region, and  that it was  not peculifLr to this one deep· water lake as had been originally supposed. Mr. G.  A.  Boulenger,  F.R.S., V,P,Z.S.,  read  a  paper entitled "Fourth Oontribution to  the Ichthyology of  Lake 1'angn,nyika. Report on the Oollection of Fishes made by Dr. W. A. Ounnington during the Third Tanganyika Expedition, 1904-05." This paper will be published entire in the ' Transactions.' The following papers were also read ;-1.  Zoological  Results of the Third  Tanganyika Expedition, conducted  by  Dr.  W.  A.  Ounnington,  1904-UlO5. Heport on the Mollusca.  By EDGAR A.  SMITH. [Eeceivcd February G,  1906.J (Plate X.t) ,  The small collection of Mollusca obtained by Dr. W. A. Ounnino'-' ton in Lake Tanganyika does not contain any important aclditign t~ the  thll.lasso.i~ series.  The.re  are some  interesting specimens of  BythocBms  u·.clescens,  tenclmg to show that  like most fresh-water  species,  it is  subject  to considerable  w{riation.  In  two cases,  Eclgw'ico and Gi1'C07,dico,  I hrwe been enabled to describe the opercui!t, which hith.erto :wel'e  unknown,  and' the collection  111so a:~ords, on~ new speCIes  of  the. genus  A nceyc,.  The various loca-lItres  fU~'Ill~hed. by J?r.  Ounnll1gton  also  add to our knowledge of the chstl'lDutlOn of some of  the fonIls.  Another matter which may be referred to in these introductory remarks is the OCCUl'rence togethCl', at  ~h~ south end  of  the lake, of  both  the  keeled  and unkeelecl Var18tles of lVeoth(,7,rJUb  t(bnganyicen~e, which,  according ~,  J. E. S. Moo~'e, 'Tanganyika Prohl"!n,' 1903, pp. 298-308. t  For explanatIOn of the Plate, sec p. 186. 1''1..;3 1906.vo1.J. PJX. 12 r I ~-L---~~~ I 17 16 15  18  19 Bole  & Danielsscn,L~~ llrlIJ. MOLLUSC.A  FROM  L,AKES  TANGANYIKA  &  VICTORlA.  I • 190G.]  OF  THE 'l'HIRD  TANGANYIKA EXPEDITION.  181 to Mr. J. E. S.  Moore *, were found by him, respectively, only at the south end and more northern localities. Living  exa,mples  were  obtained  of  Lirnnotroch1.tS,  J.'iphobia, BythoC61'(tS,  Pal'arnelcLnia,  LC6vigeria,  Ndga7'iet,  Gir'e6zulict,  allrl Anceya;  and these it is proposed  to  p1>\,Oe  in  the hands  of  an expOl'iencec1 anatomist for investigation.  The last three of  these thalassoid  genera  have  not  been  mmtomically  examined,  and therefore it will  be of  interest  to ]mow their relationship and systematic  position, and it will also  be  interesting to  see  if  the conclusions arrived at, in respect  of the rest, coincide  with the resul.ts  of  Mr. Moore's  investigations  of  them.  In concluding these prefatory obsel'vationfl  on. the  marine-like  for111s,  I  would again t  call attention to the  fact that M. Bourgnignat hn,d  em-ployerl the term " thalassoicl " in connection with them long before the invention of the compound" lmlolimnic" by Mr. Moore. An10ng  the  ordinary freshwater  for111s,  the  discovery  of  a species of A ncylus, the  first  from  the  lA,ke,  is  of  interest.  This genns has been recorded from the Victoria Nyanza, but not from the other brge lakes  of  Oentrl1.l  Africa.  Being,  howel'er, such small  objectR, and  difficult  of  observation, they mrw have easily been overlooked t. Of the few species obtained by Dr. Ounnington in the Victoria NyfLl1Za,  two  H,ppearto  be  new,  namely,  n  Corbic~tla  and  a Sphmri,ltrn, both closely nllied  to  one  or othel'  of the  few  forms already known from this lake. r.  Species /7'0111  Lake Tanganyilca. et.  THALASSOTD  SPECIES. 1.  OHYTRA  KIRKU (Smith). I!c.b.  Tembwi, a little below middle of west coast, 20 fath. 2.  BATllANALIA  HOWESI  Moore. Hctb.  Niamkolo, south end of lake. The (limensions  of  this species, which hflve never been stated, are :--Length 30  millim., diaII1.  22;  aperture lIt long, 10 broad. 3.  LIMNOTROCHus  THOMSONI  Smith. Hab.  Nclanvie, east  coast  towards  the  north  end of  the lake, 10 fathoms, also at south end. 4.  TIPITOBIA  HORE!  Smith. Hab.  !tab, at south end of lake. * 'l'ho 'l'anganyika Problem,' p.  149. t  See Proc. iVIalac. Soc. vo1.  vi. p. 78. t  11'1.  Louis Gel'main has recontly briefly dpscrihell  from'l'anganyilm  new  specios of Planorbis, Vivipara, and Oleopat1·a.  Bull.  JVI us,  Hist.  N at.  Paris, 1905, 110.  4. pp. 254-261.  ' 13* 182  MR.  EDGAR  A.  SMI'l'll  ON  TilE  MOLLUSCA  [Mal'. 6, 5.  BYTllOCERAS  IRIDESOENS  Moore.  (Pla,te X. figs.  1-3.) HC6b.  Niamkolo, south end of lake. The series of  specimens now available for  examination shows that this species, like most  freshwater  forms,  exhibits consider-able variation in size, form, and sculpture.  The much enlarged figure  in  the  Proc.  Royal  Soc.  1898,  vol.  lxii.  p.  452,  fig.  1, reproduced in the Proe. Malac. Soc.  vo1.  iii. p.  93, fig.  1, exhibits an extreme development of  the anterior or basal spine, such itS I h~1Ve  not  seen  in any  specimen.  The  largest example  in the present collection  is 44  millim. in length, and the spire is much longer in proportion to the length of  the body-whorl than in the shell depicted by Mr. Moore, and the sculpture is altogether finer. A smaller variety, but equally adult, is  more  strongly sculptured than the large form and only 30 millim. in length. 6.  BY'l'IIOOERAS  ~HNOR Moore.  (Plate X. fig.  4.) Hab.  Tembwi, west coast, a little below middle, in 20 fath. A  single  specimen  only.  I  am· inclined  to  think that  this species  will  eventufLlly  prove  to  be  fL  variety  of  Pm'amelanicl cra88igmnt~lctta.  In the  chltra.cter  of  the shells,  opercula,  and radulm  there  seems  to be  very  little  to  separate  the  genera BythoC87'CtS and Pa?·mnelanin. 7.  P ARAMELANIA  CRASSIGRANULATA Smith.  (Plrtte X. figs. 7, 8.) Hab.  South end of the lake. One very large specimen, 37 millim. in length. 8.  PAltAMELANIA  DAMONI Smith.  (Plate X. figs.  5,  6,  9.) Hab.  Tembwi, near middle of  west COfLst  of  the lake, 30 fath. ; Mrumbi, south of rrembwi, 40 fath.;  Mshale, east coast  towards the north end of the In,]m,  25  fath.;  also south end. The single specimen from the last locfLlity resembles the variety im]J6rialis rather than the typical form. 9.  LAVIGEltIA  GltANDIS  Bourguignat.  (Plate X. figs.  10, 11.) HC6b.  Mbete, south end of lake, on rocks in shallow water. A few specimens  rather smaller than the type  (P. Z. S. 1881, pI.  xxxiv.  fig.  2() (6),  with  the oblique  plications  less  strongly developed. 10.  EDGAltIA  NASSA  (Woodward).  (Plate X. fig.  19.) DClb.  Kirando, east coast of lake towards the south end. A  few  specimens  of  a  small  variety.  Operculull1  simill1,r  in character  to  that  of  LC6viqeric6  g1,(lnd'is,  horny,  dark  brown, hroadly ovate,  nucleus  ll1fLrglllal,  nel1,r  the lower  end  sculptured with fine  lines of growth.  ' 11.  EDGARIA  PAUCICOSTA'l.'A  Bourguigllat. Dab.  South end of the lake. Two mther large specimens,  21  millim. in length. 1906.J  OIr  TIlE TIlIRD  TANGANYIKA  EXPEDITION. 12.  1'ANGANYICJIA  RUFOFILOSA  (Smith), VUI'. Hnb.  South end of lake. 183 One very black specimen, having evidently been stained in black mud.  It is very different  in  shape  fl'om the  type,  being more ovate, with a longer spire, and the umbilicus nearly closed. 13.  SPEKIA  ZONA'l'A  (Woodward). HCGb.  Niamkolo, south end of h"ke,  on stones in shallow water. 14.  GIRAUDIA  IlOREI Smith.  (Plate X. fig.  13.) Hab.  Mrondwe Ba.y,  ~outh emI of lake, 10 fath. A  few  examples,  rather  smaller than  the  type.  Operculum ovate,  horny,  brown, paucispiral in the middle,  with concentric lines of growth at the outer nmrgin. 15.  GIRAUDIA  PR/ECLARA Boul'guignat.  (Plate X. fig.  14.) HClb.  Moliro, west  coast of  south emI  of the lake, on  rocks in shfl.llow wa.ter. A few specimens, rather sl11fl,ller thfln  the  type.  The  minute horny operculum, 1  millim. in length, consists of  a single whorl, the  nucleus  being  subcentru,l, but  llefLrer  the  lower end.  It is subovate, being rather narrower below than above. 16.  ANCEYA lWFOCINCTA,  sp. n.  (Pla.te X. fig.  12.) Shell  small,  elongate,  subula.te,  imperforate,  yellowish  horn-colour, with  H,  dark red  band  at the upper part of  the  whorls. Whorls  13,  slowly  increflsing,  slightly  convex;  apical  whorls probably smooth Bond  convex, 1,he two topmost remaining with two spiral  threads  round the middle  crossing  the costre, wl1ich  are much finer and more numerous than those upon the lower volu-tions.  Oostre  strong, oblique, about twelve or  thirteen upon the penultimfLte  whorl,  those  UPOll  the  body-whorl  terminating t"bruptly fLt  n.  strong spiral l'idge which encircles  the base.  In a young specimen  thil:l  ridge is  absent,  so  that  probl1bly  it  only occurs in adult shells.  Apel·ture oblique, broadly  sinuated  above and below; peristome continuous, brownish, outer margin thickened, a little expanded, columellar side also thickened and l'eflexed, with a (listinct tooth or fold at the upper:  part, joined to the outer lip by  a  distinct  callus.  Operculum  none?  Ilength  8~  millim., dia,m.  2~; aperture 2 long,  l~ broad. HClb.  Kirando, towards Houth end of the east coast, 10 fath. Apparently differing from the two known species of  the genus AnceycG in colom', form  ox  the apertlue, ltnd the clmracter of  the costre.  A.  gi1'aZlcli  Bourguignat  has  a,  palatal lira.tion  which  is absent  in  the  present  species.  In  his  figures  the  outer  lips have the a.ppearance of  IJeiug drawn from broken specimens.  If, however, they are normal, they are very different from the labrum of  the present species.  In a young specimen both the basal keel and the columellar tooth !U'fj n.bsent,  so  that these are probably 184  MR. EDGAR A.  SMl'rn  ON  THE  MOLLUSOA  [Mar. 6, fentures which nre only developed in adult shells.  Having broken up one specimen, I  failed to find an operculum. b.  NON-THALASSOID  SPECIES. 1.  LIMNLEA  NATALENSIS  Krl1uss. Hnb.  Swamp at 1V[bete, south end of lake. 2.  ANOYLUS  '£ANGANYIOENSIS,  sp. n.  (Plate X. figs.  17, 18.) Shell  very  sml111,  rOl1nrUy  ovate,  moderately  elevated,  thin, brown,  finely  radifttely  striated  across  the  concentric  lines of growth;  apex obtuse, boss-like, circumscribed, ra,diately  striated, Hubcentral or a trifle towards the right; interior glossy, exhibiting through the semitransparency of  the shell the external sculpture. Length 2~ millim., dimu. 2,  height 1. Hab.  On a stone dredged in a few fathoms in Niamkolo Ha,rbour, south end of lake. Thifl  is the first and only species  of  Ancl?l~~s known from the lake.  The genus, howevel', occurs both in the north and south of the Africnn  continent, but with the  exception of  A.  8t~ddmanni Mlu·tens, from the Victoria Nyanza, no species have been recorded from the great helms.  Being so small it is possible they may have been overlookerl. Prof.  Gwatkin,  who  hf1s  very  kindly  eXf1luined  the  mdula, observes :-"  As  I  expected, it belongs to the A. pW,(blleltb8 type, which I  ha,ve  from  S.  Africlt,  Australia,  and North and South America.  To  it belong  my  'Gundlachins' from  Tasmania and New Zealand." 3.  PLANORBIS  SUDANICUS  Mm-tens. lIab.  Swamp at lVlbete, south end of lake. 4.  NEO'l'HAmrA TANGANYICENSE  Smith. lIab.  Kitnta, Kala, Molil'o, Sumbu, Kalambo. Keeled and non-Cftl'inate specimens Wel'e found too'ether at the south end  of  the lake  by Dl'. Ounnington,  so  that'=' Mr. Moore's ide11  of  t~le local  distribution  of  this species  appears to be, in fl, measure, Ulcorrect. 5.  A~lPULLARIA OVATA  Oliviel'. H(bb.  South end of lake. G.  UNIO  BUlt'l'ONI Woodward. Hab.  !:louth end of lake, a,nd  Kahl [Lt south encl  of east coast. '7.  BUR''l'ONIA  'l'ANGANYICENSIS  (Smith). H(bb.  Rombe, east eoast below the middle, and south end of the lake. 8.  PLEIODON  SPEKEI  vVooclward. Hab.  Sumlllla, east coast. 1906.J  OF  1.'IIE 'rIIIRD  TANGANYIKA  EXPEDITION,  185 9.  BRAZZAllA  ANCRYI  Bourguignat. HC6b.  Kibi1nga. One  valve  only,  with  five  or six  radiltting  ridges  down  tlle f1l1teriOl'  end. c.  POST-PLIOCENE SPECIES. Some  shells  of  species  still  living in Tn,nganyilm  were found embedded  in a  coarse  sandy matrix upon the shore at Smnlma, about  halfvmy  up the east coast  of  the lake.  One  reef  was so  weathered that the shells  (NeotluGW1U6)  stood out  very  con-spicuously,  just in the  breakers.  Thl'ee  si111i1a,r  reefs  occur  at intervals  inland,  on the  sunnnits  of  the former sandy beaches. These shells may be referred to a  In,te  Post-Pliocene age.  Other specimens occurred in a  cliff  or  ridge, about six feet high, in the north-west  part of the Rukwa Valley,where the lake formerly was,but is now dried up. So far as one can judge, nOlle  of  the shells which are more or less pm'fect, or of those of whieh there are only fra,gments, belong to other than recent species, t;howing that these liclges are of quite modeI'll origin. Among those from Sumbua, besides the J.V(3otha~G'fna, are remains of Rwnella, a thalassoid genus, and of Un'io;  [],nd from the Rukwa Vnlley are  fra,gments of  Lanistes,  Vivipcll'c6,  JlfelanicG,  COl'bilYltlcG, a,nel  llnio, fLU ordimll'J fresh  water types.  The amount of material at ha,nd, however, is so  smtLll,  that one  cannot say to what extent the thalassoid shells ITmy  be represented in the s  •• me locality. n.  Species from the  Victoria .Nyanza. 'fhe  following  specieR  were  ohtnined  by Dr.  Ounnington  a,t Bnkobn on the west shore of the Lake. 1.  PLANORBIS  SUPANIOUS  Martens, var. MINOR  iVra,rtens. HCGb.  On water-weed in shallow-water inlet north of  the town. 2.  PLANORBIS  CRAWFORDI  Melville &;  Ponsonby. Nab.  Same as tlmt of preceding species. Two specimens were  obtained, which appear to  be  insepamble from this species described fi'om  Cape Oolony. 3.  MELANIA TUBERCULA'rA  (MUller). IIab.  Taken  in  shrimp-net  in  a  few  feet  of  water  in  the harbour. 4.  VIVIPAitA  CONSTRIC'l'A  Martens. 1£(Gb.  Dredged in about a,  f.tthom in the lmrbour. The specimens  of this very variable species  from  this locality are rnther like Martens's figure (' Beschalte Weichthiere Deutsch·-Ost-Afrika,' vol.  iv.  pI.  vi.  fig.  20), but they exhibit it third keel between the two represented  in the illustration.  They are more 186  MOLLUSOA  OF TilE THIRD  TANGANYIKA  EXPEDI1'ION.  [Mar. 6, strongly spirally striated than other examples  which have been examined. 5.  UNIO  LOURDELI Bourguignat. Hab.  Dredged in about a fathom in the har·bour. 6.  OORBIOULA  OUNNINGTONI,  Rp.  n.  (Plate X. fig.  15.) Shell small,  irregularly ovate,  almost  equilateral,  moderately convex, sculptured with  rather  distinct  and  distant  concentrie ridges, which become almost obsolete on both dorsal slopes;  valves yellow olivaceons, with  01'  without a  few brownish rays, more or less  deep  purplish  within;  umbones  prominent.  Length  12~ mi1lim., cliam.  8, height 11. IIc6b.  Dredged in about H,  fathom in the harbour. This species  may be  separated from  C.  mdiata Parreyss,  the only species recorded from the Lake, on account  of  its somewhat different  form,  the  umbones  being  more prominent,  the  more dista,nt concentric ridges, and it difference in colour.  None of the specimens exhibit  the characteristic  dark purple ray proceeding from  the umbo  down  the middle of  the valves as  in C.  mdiatc6. Two  out of  tlu'ee examples have little or  no  trace of  marking:.;, but the third is  distinctly  rayed with  brown,  the  rays  being different in the two valves.  ' 7.  SPil.iERIUM  VIOTORVE,  sp.  n.  (Plate X. fig.  16.) Shell roundly subovate, nearly equilateral, greyish yellow, with numerous  radiating dark hair-like lines;  valves thin; finely con-centrically striated with the lines of growth, which are crossed hy minute microscopic radiating strire which are quite invisible to the naked eye;  interior dirty bluish; lateral teeth delicate. Length 9i millim., diam.  5~, alto st. Dab.  Dredged in about a fathom in the harbour  . . Larger.  than  S.  nya,nzce  Smith,  not  quite  the  same  shape, dlfi'el'entm colour, rayed, and with more delicn,te hinge-teeth. 8.  iETllERIA ELLIP'rICA Lamarck. Hab.  Entebbe, north-west end of the lake. EXPLANATION OF  PLATE  X. Figs. 1,2,3. Bythoce,'as i1'irlescens:  p. lSg. 4.  "  min01':  p. 182. 5, 6, 9.  Pa,'amelania damoni: p. 182. 7, 8.  "  c"a ssigJ'anmlata:  p. 182. 10.  LavigcJ'ia [f"andis: p. 182. 11,,,  "operculum. 12.  Anceya TUfucincta:  p. 183. 13.  G-;"andia "01'8i,  operculum: p. 183. B.  "  p"mcla"a, operculum:  p.  183. 15.  OOJ'bicn7a C1tnningtoni/:  p, 186. 16.  SphmJ'i"'" victo"irB:  p. 186. 17, 18.  Anc,1fZ,,"  tanganyioensis:  p. 184. 19.  Ed[fa?'ia nassa, operculum: p, 182. 

Zoological results of the third Tanganyika expedition, conducted by Dr. W. A. Cunnington, 1904-1905 : report on the Mollusca

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