Bulletin of the United States Fish Commission Seattlenwf
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THE MOL1,USCA OF I'OKTO ICICO. BY c 0 N T E N T s . Page . Introductioii ........................................................................................ 353-358 Description of the mollusks ......................................................................... 358-498 Check list of tlic mollusks .............................................. ........................ 499-513 Liet of U . 8 . Pisli Commission stations .............................................................. 514 b:xpIsupRlioii of the plates........................................................................... 615-516 Index ............................................................................................... 517-524 352 THE MOI,I,USCA OF PORT0 RICO. BY W. H. DALh AND e. T. SIMPSON. INTRODUCTION. The following report on the niolluslis of Porto Rico is the result of a study of collections made by the U. S. Fish Coinmission steamer fi%h IliciaX’ during explora- tions of that island in 1899, arid of the antecedent literature. But little attention seeins to have been paid to the Yorto Rican marine mollusk-fauna, considered sepa- rately from that of the West Indies in general, and only the land shells are at all well known. The principal sources of information arc: (1) R paper by Shuttleworth on some land shells of the island; (2) a monographic sumniary of the land and fresh- water shells, by Crosse;’ (3) II similar summary of the whole mollusk-fauna, including the 1n:irine forms, by Gundlach; a (4) a brief paper on the land snails by von Marter~s:~ The rest of the information is scattered through the literature of the West Indies and niolluslcs in general, from very early times. As with tho West Iridian fauna in most branches, apart from the birds and land shells, information as to the species is fragmentary and unsatisfactory, no equal area of the shores of countries equally long known anywhere else in the world being so imperfectly explored and with the recorded data in such great co1ifusion. The sea-shell fauna of the West Indies was ‘the source of a large proportion of the shells known to the earliest writers, and I~I~Y be said to rank third in the order of importance in its contributions to the early iconographies, coming next after the European and Indo-Pacific regions. The localities were often stated erroneously or as ~nkno~~n,and the same inay be said of the great iconography of Xeeve and Sowerby, based on the Cumingian collection. Many West Indian shells are there depicted with erroneous localities, and shells not known in the Antillean region are referred to it. The similarity of Spanish names in the Pacific, Oriental, and East Anierican regions is no doubt partly responsible for this confusion. A few later lists, such as those of Beau and Fischer for Guada- e; Krebs and Morch for the West Indies; Guppy for Trinidad; Poulsen for St. mas; d’Orbigny, in Sagra, and Arango, for Cuba, have done something toward clewing up the subject, yet it is still in a deplorably unsatisfactory state. Some years ago the senior author of this report published an index to the Periodical literature and- fugitive papers on the malacology of this region,6 in which ’ Robcrt James Shuttlcwortlt. Beit&ge zur 11Bherett ~enntnisdderLand- nnd SiiSa\Vfl~uer-hlOlluNkellder I1lve1 Pokto Hico. blitth. der Naturforncheiidoll GesellmhaIt in Bern, 11. d.,Jahre1854. 8O. pp. 3G-58,imtrs 1851, and 89-103,Julli 18-54. .‘Joseph-Uharles-Hippoiyto Grouse. Fitunii m~lacologiqueterrestre et fluviatile de I’lle de form-Itlco. Journ. de collchyliologie, XI, pp. 6-71,lS‘JL. Also iwued separately in coVc1’8. a Don Juan Gundlacll. Apltrttes pjira 18 fauna Puerto-Riqoefia. Partes cuarto y qllintn. Analeh de la SOC. PAP. de Hkt. Nit., XII, pp. 5% awl 441-184,1~.A180 iw~~efiscpnmtely. 8’. Edllard ”011 hiartens. and. tlnd ~l~~~qwj~~~~’~-~r]l~t~r~[~l,yon Porto~lro. Jtihrlnlc-h dm 1)cutnchnl n~sl~kologiscl~en cic5elJschnft, IV, pp. 340-36i. 1877. f~Br1llctinof tho U. S. QeoiogiCnl Sorvey, NO. 24. I,jst 01 the ~ilnri~~o~nollnscn from American localities between Capo uatterns and Cape i{oque, iilcludiug the ~~rmudas.BY Williuln ~ea~eyDall. ~llshington(the Survey), 18x6. 3% PP. 8’. B. C. B. I‘WJ-23 353 354 BULLETIN OF THE UNITED STATES FISH UOMMISSION. refcrenccs only, without any attempt at synonymy, were given for all citations 01 specics supposed to be from the West Indics and adjacent shores. Considerablc additions have since been made in the Blake Reports, the Proceedings of the Unitod States National Museum, the Nautilus, and elsewhere. A ~upplementto the bulletin referred to, which should include the species cited from this region in the iconog- raphies and the later issues of the periodicals mentioned, would be of immense service in helping to bring order out of the existing chaos. Meanwhile all carefully determined lists of species from definite localities are of the utmost value, and only when a large number of these have been made can we expect to utilize the facts of inter-island or bathymetric distribution. The present report is intended to be of this character. Great care has been taken to identify the species correctly, while the question of ultimate nomenclature has in great part been left in abeyance. It is believed that the names assigned in ‘every case belong to the species designated; but whether in all cases the designation used is the first which was ever applied to the species in question we have not attempted to determine, though in most cases it is believed to be so. At the request of the authorities of the Commission, who hoped this report inight be to some extent utilized as a handbook for the mollusks of the island, a brief description has been prepared by Mr. Simpson of the genera, subgenera, and species present in the collection. This has been a work of considerable magni- tude and has occupied ii great deal of time. The portion of this report relating to the land shells is entirely the work of Mr. Simpson, who has also had the task of compiling the list of species not represented in the Fish Commission collection. The work of the senior author has been chiefly devoted to the revision and verification of references, the confirmation of the identifications of the marine forms, the descrip-. tion of new marine species, and general editorial supervision. Our intention has been to give a reference to the place where a species was originally described, and to a figure, without attempting elaborate synonymy. Sev- eral species hitherto unfigured, though described half a century ago, have nom been figured from the author’s types. Nearly all the new species are figured, and also a few forms not new or unfigured, but which are especially characteristic of this island, such as Pleurodmte ccurocolla. It has been one of the surprises that II number of species originally described from deep water in the Blake Reports turned up in less than 100 fathoniri in Mayaguez Harbor or other localities. It is evident that a thorough cxploratio with the mollusks especially in view, and systematically conducted dredgings, would add very materially to the list now presented. In a discussion of the number of marine species normal to a fauna in given .zone of temperature’ the conclusion was arrived at that, omitting strictly abyssal species, the average marine American tropical shell-fauna comprises about 581 species, id, as none of the faunas cited could be regarded as thoroughly known, it would doubt- less he well within the mark to call it in u round number 600 species. Porto Itico has a sufficient variety of coast, with rocks, flats, sheltered harbors, currents, wid subinarine tloclivities, to sustain a fully average representation of the - __ - ..-- ._ - --. - __ - I Hiilletin of the KJ. S. Qeolo~icaISurvey No. 84. Correlation Papem Ncoc*et~o,by Willintn HotLley Dall wid bert Ikuninon Harris. Washington (the Survey j, 1892. 80. pp. 349. Sue pp. 2631. MOLLUSCA OF PORT0 RTCO. 355 marine fauna of the region of which it forms :t part. Tho oxtr;iordinary richncss of some spots, as iii Mayaguez Harbor, where tt few hauls of the dredge were taken, affords sufficient evidence that there is no unusual paucity of molluscan life about the islarld in proper situations. Hence we may reasonably expect the total census of shell-bearing mollusks, when carefully made, not to fall short of the average above indicated for such faunas. Excluding land and f resh-water shells, and nudibranchu, the total number of species and well-marked varieties included in the present report is 530. We may therefore suspect that about 70 marine species, actually existing soirieivhere about the island, remain to be collected and identified before our catalogue car1 be regarded as approximately complete. The most interesting feature of,what we may call the West Indian fauna as a whole is its extent beyond the limits which have been ordinarily assigned to it. Off the eastern coast of North America, outside of the narrow strip of colder water which Illalces its way close inshora nearly to the coast of Georgia, the West Indian fauna in the warm waters of the Gulf atid equatorial currents extends northward over the vast area of the continental plateau tind slope fully to the latitude of Cape Hatteras, :LS has been proved by the dredgings of the U. S. Fish Commission. On the soutli tho species extend along the coast of Brazil to the estuary of the River La Plata, though in constantly diminishing numbers. As on the Pacific shore the Panatnic fauna stretches from Point Conception, Gal., south to the Bay of Guayaquil, so the companion fauna of the M‘est Indies covers an even greater extent of coast, on which it inay doubtless hereafter l)c divided into a certain nuniber of subordinate faunulie. The fact that the stretch of cold now sterilized by the fresh waters of the Amazomas has not Nctetl ILS t~ barrier is tolerably good evidence that the existing distribution, in its nitiin features, antedates the foi*rnatjon of this immense river system.