C7 gz =F WAIN VINA AN an ) i; William nlealey Deal SZ, ea Ee (A . B bk Y @ ONC cc eww wc ont ee ew ew ew eee owe oo Ss wert em me me eee ce ee ewe we ee eew eee et lis DEG ZZ i i ") Wy) Vj LY) f i y ty xh © I °o eS eet se at ae iene > ae winion ® o o > = - fi 2 - a ; | : : a» i | Ae 7 7 aan Bs | LP 7 , on — * — a = ia me 7 > | im ! } 7 ‘ Poul U r es my of a , ' =r ' 5 7 ‘ [ 7 le | "4 a : . a : ~ 7 _ a ’ i “oe ; | - 7 7 oF a O —— ' eer s ) ce > , 7 ‘rts ae im aed! Ga - a 7 ann : A *@ : 7 oe 1 ; ’ - > os y y 7 = - > - ¥ > “ a a _ a —_ a : a CATALOGUE Sie ‘ j oF THE REIGEN COLLECTION MAZATLAN MOLLUSCA, ) BRITISH MUSEUM. WARRINGTON: PRINTED AT THE OBERLIN PRESS, BY P. P. CARPENTER. 1855-7. Ye As PREFACE. Tue Collection, from which the shells described in the following pages have been carefully selected, was made at Mazatlan, (Jat. 23° N., long. 1079 W.) during the years 1848-50, by a Belgian gentleman named Frederick Reigen. The bulk of it was sent to Liverpool for sale in 1851, and circumstances enabled me to make a searching examination of it. Dr. Gray having requested that the (comparatively) small selection which I had made for my own use should be deposited in the British Museum, I judged it conducive to the interests of science to obtain possession of the whole of the then-remaining stock, which was about to.be dispersed ; and to select as many specimens as might be required (1) to illustrate the local-fauna of a known station at the mouth of the Gulf of California ; and (2) to exhibit the amount of variation, whether great or little, observed in comparing together large numbers of in- dividuals in the various species. The latter object appeared of no slight importance, especially for the sake of inland natural- ists ; who have usually to depend on the very limited number of specimens which are generally to be seen in public, still ‘more so in private collections. The series of shells here enumerated is presented to the Trustees of the British Museum, and accepted by them, on the following conditions :—(1) Dhat tt be preserved separate and intact, as a local collection: (2) That tt be always open to the use of students, subject to the usual conditions: (3) That the donor be allowed to arrange the collection in its permanent place of abode: and (4) That a Descriptive Catalogue of it be printed under the direction of the Trustees. The collection consists of about 8873 specimens (2505 Bivalves, &e., and 6368 Univalvés) mounted on 2529 glasstablets.* The number to the left refers to the species, that to the right to the * The following are the advantages of this mode of preserving specimens, either in public or private collections. (1) Both sides of the shell can be seen; thus combining the advantages of mounting with those of leaving loose. (2) The drawers or cases can be lined with any coloured paper that happens best to display the particular series. Very dark purple or black, glazed, will generally be found most suitable. (3) The tablets and shells can be cleaned as they stand, without remounting. (4) The tablets are extremely cheap, and can be rapidly eut to any required size. To write the names, white paint sbould be worked. with a pestle in a little turpentine, till it is thin enough to pass through a fine steel pen. The strongest cement is common shell-lac dissolved in spirit; but the bleached liquid glue has a better appearance. ‘The minute shells in the col- lection are cemented with Canada balsam to strips of thin glass, which are fastened into the corks of test tubes. 1y. PREFACE tablet inthe Catalogue. Of the minute specimens, magnified sketches are given, drawn under the microscope with Chevalier’s prism-dise. The principal part of the money required for the purchase of the shells has been generously and without solici- tation provided by Herbert Thomas, Esq. of Bristol. For the remainder, and for all the work, from the first sorting and wash- ing to the permanent allocation, (including no inconsiderable share in the manual labour of printing,) Iam alone responsible. The duty of writing the Catalogue was intrusted to me by Dr. Gray. I was ill fitted for it, (1) by almost entire ignorance of conchological literature, and (2) by living in a country town, with extremely limited aecess to scientific books and collections. There did not appear however any competent naturalist who possessed the absolute essentials of time and full access to the Mazatlan materials. I therefore undertook the task, trusting that its acknowledged deficiencies might in some measure be compensated-for by great patience and care in the faithful use of those means of information which were within my reach.* I have endeavoured to make it a companion to Prof. C. B. Ad- ams’ extremely valuable Catalogue of the Shells of Panama, _which belong to the same great Tropical Fauna of W. America. An estimate of the value of the Reigen Collection as a geographical authority, and a comparison of it with other neighbouring faunas, will be found im the “Report of the pre- sent state of our knowledge of the Mollusca of the West Coast of N. America” presented to the British Association in Sept. 1856. and published in its transactions, pp. 159 ef seg. The = In the course of the inquiry, I have met with the greatest kindness from naturahsts, most ef whom were previously unknown to me, but to whom I applied for assistance. To Hugh Cuming, Esq. lam under extraordinary obli- eations for his singular urbanity, in allowimg the unrestricted use of his mvalu- able collections. his Hbrary, and his original information to a complete stranger. Dr. A. A. Gould, of Boston, U. S. intrusted to my care, and to the perils of the Atisntic, the whale of his collections and notes from the W. American coast, for comparison with those known in this country. To Dr. Gray and R. M’Andrew, Esq. I am indebted for the long use of valuable works, and for advice and assist- ance throughout. Prof. Dr. Dunker, of Marburg, gave me valuable sid in the Mytilide, J. D. Gaskein. Esq. im the Cypreadz and Columbellicde, L. Reeve, Esq. in the Patelliide, W. Clark, Esq. and W. Bean, Esq. im the Cecide, J. Alder, Esq. in thst family and in Jeffreysiade, and Miss Steere in Olivide. 8. Hanley, Esq. sllowed me the use of his collection, (representing the Havre division of M. Reigen's stores,) and, slong with R. D. Darbishite, Esq. Dr. Baird, Messrs. H. & A. Adams, Rev. T. Hinmcks, S. P. Woodward, Esq. and F. Archer, Eaq. gave the benefit of eritical judgment and experience whenever solicited. I am aiso under great obligations to the officers of various public museums and libraries, for the kindness with which they have attended to my requests. One whose promised aid would have been of invaluable service, and whose friendly encouragement mainly induced me to undertake the work, was, at its com- mencement, suddenly removed from the field of Isbour which was opening before him with such promise in the metropolitan university of Scotland. PREFACE v. only account of the shells of Mazatlan previously known, is Dr. Menke’s list of the species brought by Mr. H. Melchers, published in the Zeitschrift fiir Malacozoologie, 1847-51. An analysis of these is given in the Brit. Assoc. Rep. pp. 235-239. The species of Bryozoa,* (now first, I believe, included in a catalogue of Mollusca, although generally acknowledged by naturalists to belong to that Subkingdom) have been described by G. Busk, Esq. with his usual kindness. The class is named as in Dr. W. B. Carpenter’s “Principles of Comparative Physi- ology, 1854.” The name Polyzoa is believed to have precedence: but while the names of genera and species are proper names, and therefore ought to follow the law of priority, the arrange- ment of classes and orders is a matter of opinion ; and it appears allowable to make use of those names, whenever given, which best express the leading characteristics of the division. For this reason Palliobranchiata and Lamellibranchiata are used instead of the older names Conchifera and (or rather, including) Brachiopoda ; Proboscidifera for Zoophaga, &c. In the pre- sent case, when the name of a supposed order (of Polypes) becomes entitled to rank as a Class (of Molluscs), and as such has to be learned in common schools, it appeared very important to select a name that could not easily be confounded with others of similar sound: In the bivalves, the order of Prof. E. Forbes, adopted by Mr. Woodward in his invaluable ‘‘ Manual of the Mollusca,” has been mainly followed : in the univalves, that of Dr. Gray, who obligingly lent me the proof sheets of his “Systematic Arrangement of the Mollusca” now passing through the press. I am not possessed of sufficient knowledge of physiological anatomy to give an independent opinion on disputed points. Having found considerable difficulty in the identification of species, when Lamarckian genera are retained without division, although now as numerous and diversified in recorded forms as were many of the Linnean genera in the days of Lamarck, I have freely adopted many of the generic names recently pro- posed, and have even, in some few cases, addedtothem. Itisa matter of secondary importance, whether an accurately defined group takes rank as a mere section in a subgenus, or as a lead- ing division in a family: but the binomial designation is much easier for reference than that by sections. For ordinary purposes * The Crustacea, Cirripedes, Annelids, Radiata, &c. found in the Reigen Collection, are deposited in the Warrington Museum ; which has the honour of beimg the first Free Museum and Library established in the manufacturing dis- tricts. Duplicate series of the shells can be obtained through the Curator. Vi. PREFACE it may be sufficient to cite the lower division, the genus (like the family, &c.) being implied. When the genus is required, it should have been always quoted, as it is in the later sheets, thus (Terebra) Myurella albocineta.* In naming the genera and species, I have almost always followed (to the best of my knowledge) the law of priority, with the modifications authorized in the Brit. Assoc. Rep. 1842, pp. 109 ef seq. In a few cases however, in which different forms have been described as distinct species, which I have thought it necessary to unite, I have chosen that name (irre- spective of priority) which represents the typical state of the species. By this means, those who are not satisfied with the union can keep the accustomed names for those forms which they regard as distinct, without adding to the confusion. Thus the name Dione chionea of Menke is chosen, being applicable to the whole species, of which D. squalida, Sby., D. biradiata, Gray, D. chione Sby. (pars), and perhaps D. elegans, Koch, had been previously described from peculiar forms. To have dispensed with no fewer than 104 species constituted by naturalists of reputation (exclusive of synonyms), and at the same time burdened science with the names of 222 new ones, in a list numbering not quite 700 species, may seem extremely presumptuous in so inexperienced an author; as also may the opinions freely expressed on various recorded statements. But fresh sources of information must always be expected to modify judgments formed from insufficient materials: and, as a natu- ralist should desire truth above all things, and wish to save others the necessity of wading through the same labyrinth of errors from which he has with difficulty extricated himself; it appears a duty to lose no opportunity of correcting those state- ments in previous works which are liable to create confusion. The first person has been frequently used to shew that the statement put forth is not necessarily a fact, but simply my interpretation of a fact: and for a similar reason I have freely employed the mark of uncertainty [?], which is to be under- stood as always referring to what follows, and not the word going before. Thus Bulla ?nebulosa, Gld. signifies that it is uncertain whether the Bulla belongs to Gould’s species: while ? Alaba conica signifies that the generic position of the species conica is doubtful. * It would save much confusion if those wh divide genera would always make the subordinate names of the same gender with the original genus : also if authors, in describing new species in old genera, the modern ‘divisions of which are not generally recognized, would avoid repeating a name already given in another of the sectional groups. Vide Brit. Assoc. Rep. Joe. cit. PREFACE Vil. As the proposed object was to exhibit all that was known of a local fauna, many species are described from more cr less imperfect materials, which would not have been noticed if from a mixed collection. The same course is usually followed in describing the fossils of any given formation, where objects are carefully noted that a mere collector of “good shells” would cast-aside as worthless. There appears no reason for denying all knowledge of existing forms, merely because that knowledge is not as full as may be desired. In spite of the interests of classical Latinity being freely sacrificed, whenever those of brevity come into collision, the diagnoses of species will generally be regarded as much too long. The reasons are, (1) that I generally had to describe not single specimens, of which a literary picture could be drawn, but a large number, all whose observed differences had to be inelu- ded: and (2) that, in our present state of very limited know- ledge, it is necessary so to describe as not only to separate the object from previously known species. but from other similar ones that may be hereafter discovered. Those who have en- deavoured to identify critical species from the descriptions of some of the early naturalists, would willingly part with the acknowledged convenience of brief diagnoses for the sake of a greater approach to accuracy. When a fauna (like the British) has been well explored, a careful analysis of species may allow of their identification with but few words of separative descrip- tion. In many instances, the materials at command were not sufficiently clear to decide whether differences of form were of specific or only of varietal value. In these cases, they are generally tabulated as conspecific; but with the Pvariety separately named and described, ready afterwards to take rank as a species, or to merge into the related form, as further facts or better judgment may decide. The measurements (unless otherwise expressed) are, in obedi- ence to an authority, thus taken, In bivalves; long. from the umbo to the middle of the ventral margin; Jaé¢. from the anterior to the posterior ends; a/é. the thickness of the closed valves. In the spiral univalves; Jong. from the vertex to the base ; long. spir. from the vertex to the posterior end of the labrum ; dat. the diameter of the body whirl; div. the mean angle of divergence of the spire outlines. All the measure- ments of length are given in inches and decimal portions. In describing sculpture, (the words longitudinal and trans- verse not havingbeen always used in the same sense) the follow- ing terms have been generally employed. In the bivalves ; con- Vili. PREFACE centric, in the direction of layers of growth; radiating, from the umbo to the margin. In the spiral univalves ; radiating (from the axis of the shell), in the direction of layers of growth; spiral, along the whirl, parallel to the suture. In comparing the words used to describe sculpture (lire, lirule, strize, striule, &c.) with the same words in other books, they should often be interpreted as to the appearance of the shell under the micro- scope, generally with an inch-achromatic. The vertex applies to the whole nuclear portion ; but the apex only to the first whirl. Asa slight twist in this may, or may not, be estimated asa whole turn, the number of whirls, as stated by different authors for the same shell, may sometimes vary.* In citing geographical authorities, the name of the first observer (not necessarily the collector) is distinguished by Italics, in preference to the mark [!| now frequently used; since itis not a matter of surprise, but of emphatic fact that a certain person brought a shell from a particular place. The S. W. Mexican collection, frequently quoted with my initials, was brought from a port on “that coast,” probably Acapulco : vide Brit. Assoc. Rep. 1857, pp. 281-3. The terms expressing frequency are to be understood as applying to the collection when I first saw it, after several of the shells had been withdrawn by purchasers. They are to be interpreted relatively to the total number, and are generally used as follows : extremely rare, under a score ; very rare, under 100 ; rare, under 200; not common, or not uncommon, 300; com- mon, up to 400 or 500; abundant, about 600 or 700; extremely common, up to 1,000; extremely abundant, more than 1,000. The errors which arise from ignorance, those with better judgment and means of information will be able to correct. The errors of observation can easily be detected, as the shells themselves are open to all who desire to study them. It is hoped that all such errors will as speedily as possible be detect- ed and exposed ; and that this work may soon be laid aside as useless, having served its purpose as a stepping-stone to some- thing far better. The sooner our own work perishes, the truer will be our knowledge of Him whose exquisite order and beauty can be abundantly traced, even (asin the following pages) in the worm-eaten passages of a decaying shell. PHILIP P. CARPENTER. Warrington: April 22nd, 1857. * This may account for discrepancies in Vitrinella, and in the descriptions of the nuclear vertex in Pyramidellide, In this catalogue the number is over rather than under-rated. CATALOGUE OF THE COLLECTION OF MAZATLAN SHELLS, IN THE BRITISH MUSEUM: COLLECTED BY FREDERICK REIGEN, DESCRIBED BY PHILIP P. CARPENTER, LONDON: PRINTED BY OBDEK OF THE TRUSTEES 1857. PRINTED BY P, P, CABPENTER, OBERLIN PRESS; WARRINGTON. (No) PREFACE. “Mire Collection, from which the shells described in the following pages have been carefully selected, was made at Mazatlan, (lat. 23° N., long. 107° W.) during the years 1848-50, by a Belgian gentleman named Frederick Reigen.” The bulk of that portion of it quoted in the following pages‘as the ‘Liver- pool Collection,’ was purchased by Herbert Thomas, Esgq., of Bristol, and Mr. P. P. Carpenter. The latter gentleman “selected from it as many specimens as might be required (1) to illustrate the local-fauna of a known station at the mouth of the Gulf of California ; and (2) to exhibit the amount of variation, whether great or little, observed in com- paring together large numbers of individuals in the various species. The latter object appeared of no slight importance, especially for the sake of inland naturalists ; who have usually to depend on the very limited number of specimens which are generally to be seen both in publicand in private collections.” This series Mr. Carpenter presented to the British Museum, on the understanding that it should be kept separate and intact for the purposes above named, like the Cuban, South American, and other local collections: he undertaking, at the same time, to prepare a Descriptive Catalogue, which is here printed. The descriptions of the Bryozoa, occupying the first six pages, were kindly communicated by G. Busk, Esq., E.R? 8. .&e: “The collection consists of about 8873 specimens (2505 Bivalves, &e., and 6368 Univalves) mounted on 2530 glass tablets. The © number to the left refers to the species, that to the right to the tablet in the Catalogue. The minute specimens are fastened on strips of thin glass enclosed in test tubes. By this mode of arrangement, both sides of the object can be seen without disturbance.” “The measurements (unless otherwise expressed) are thus taken. In the bivalves; Jong. from the umbo to the middle of the ventral margin ; /at. from the anterior to the posterior ends; alt. the thickness of the closed valves. In the spiral univalyes ; dong. from the vertex to the base; long. spir. from iv. PREFACE the vertex to the posterior end of the labrum; Jat. the diame- ter of the body whirl; div. the mean angle of divergence of the spire outlines. All the measurements of length are given in inches and decimal portions.” “Tn describing the sculpture of bivalves, concentric signifies, in the direction of layers of growth; radiating, from the umbo to the margin. In the spiral univalves; radiating (from the axis of the shell), in the direction of layers of growth; spiral, along the whirl, parallel to the suture. In comparing the words used to describe sculpture (lire, lirule, striz, striule, &e.) with the same words in other books, they should often be interpreted as to the appearance of the shell under the micro- scope, generally with an inch-achromatic. The vertex applies to the whole nuclear portion ; but the apex only to the first whirl. As a slight twist in this may, or may not, be estimated as a whole turn, the number of whirls, as stated by different authors for the same shell, may sometimes vary.’* “The terms expressing frequency are generally used as follows : extremely rare, under ascore ; very rare, under 100 ; rare, under 200; not common, or not uncommon, 300; common, up to 400 or 500; abundant, about 600 or 700; extremely common, up to 1,000; extremely abundant, more than 1,000.” “Tn citing geographical authorities, the name of the first observer is distinguished by Jtalics. The mark of uncertainty [?], is to be understood as always referring to what follows, and not to the word going before.” “An estimate of the value of the Reigen Collection asa geographical authority, and a comparison of it with other neighbouring faunas, will be found in the ‘Report of the pre- sent state of our knowledge of the Mollusca of the West Coast of N. America’ presented to the British Association in Sept. 1856, and published in its transactions, pp. 159—368.” JOHN EDWARD GRAY. British Museum: April 22nd, 1857. * «This may account for discrepancies in Vitrinella, and in the descriptions of the nuclear vertex in Pyramidellide. In this Catalogue, the number is over rather than under-rated.” CONTENTS. PAGE. CLASS BRYOZOA. (Svecies 1—13, 677—679.) ORDER INFUNDIBULATA. SusorpER CHEILOSTOMATA. Mempranrporip®. (Tablets 1—13.) Membranipora ids 1 Lepralia ae {t 3, 6, 529 CeLLEPporipDE (Tablets 14—16. e) Cellepora _.. 5, 6 SUBORDER CYCLOSTOMATA. TUBULIPORIDE. Tubulipora a A 6 Discorporap® ‘Tablets 17, 680.) Defrancia ue 6 CLASS TUNICATA. ... Si ip 7 CLASS PALLIOBRANCHIATA. (Species 14.) Discinipz (Tablets 18—20.) Discina 7 CLASS LAMELLIBRANCHIATA. a Seesies 15— 220, 680—691, 693, 694.) PHotapipm. (Tablets 21-42.) Pholadidea cue i, 8 Parapholas_... yas 9 Martesia Le aM) 13 GASTROCHENIDE. (Tablets 43—59.) Gastrochena yt ae Ag SAXICAVIDR. (Tablets 60—64. ) Saxicava 16 PETRICOLIDEA. ( Tablets 65—74,, 781, 2516.) Petricola 17, 547 Rupellaria ( Venerupis) 20 Naranio .. 169, 529 Myipm, (Zablet 2517. ii Mya 529 CoRBULID. ins 75—89, 2518—2520.) Corbula he bf 21, 530, 547 Sphenia As aah Sie SO) Vi. CONTENTS (Lamellib ranchiata, cont.) Panporipe. (Zuablets 883—85, 2528.) ; 26, 530, 548 Lyonsia Tyleria SoLECURTIDE. ( Tablets 86—90.) Solecurtus TELLINIDZE. (Tablets 92—131, 2521.) Semele (Amphidesma) ... Cumingia Sanguinolaria Tellina Tellidora ... Strigilla Donacipm. (Tablets 132—210.) 2 Iphigenia (Capsa) Donax is ef Macrripm. (Tablets 211—215.) Mactra = Spisula Mulinia _... Gnathodon (Rangia) Venertpn. (Tablets 216—411.) Clementia Trigona a Dosinia (Artemis) Cyclina Dione Cytherea Venus (Chione) Tapes Anomalocardia Astartip&. (Tablets A12— 424.) . Circe Gouldia Cardita Venericardia ... Trapezium (Cypr icardia) Cuamipm. (Tablets 425—445.) Chama CarpiaDm. (Tablets 446—463, 2522.) Cardium Lucinipz. (Tablets 464-478, i Lucina Fimbria (Corbis) PAGE. 25, 547 27 52, 549 52, 549 54. 54, 549 81 82, 549 84. 85 86 87, 549 90, 531 96 101 CONTENTS Vil. Lam ellibranchiata, cont.) PAGE. Dirtopontip®. (Lablets 479—484.) Diplodonta ... RS 102, 549 Felania io OF LOsea49 KELLIADE. (Tablet 485—504, 2523, 2529.) Kellia 105 Lasea Be FS 107, 531, 549 Lepton ay ste 110 Pythina se i 112 Montacuta ey: ae LIDS 531 Cycntapipe. (Tablets 505—522.) Cyrena i cs 114 Unionip&. (Lablets 523—527.) Anodonta be .. 117, 550 Myritipm. (Tablets 528—607, 2530.) Mytilus ae Ae 118 Septifer ... ae 120 Modiola m, at 120 Crenella Me 123, 550 Lithophagus ( eiaianie) be 124, Leiosolenus 130, 550 ArcaDm. (Tablets 608—666, O52. ) Area 132, 532, 550 Byssoarca Be 138 Pectunculus on 144, Nvucuuipz. (Tablets 667, 668.) Nucula ; At 145 Leda A Ba 145 Avicunipm. (Tablets 669—690.) Pinna ay rit 146 Avicula 147 Margaritiphora ( Meleagr ita) 149, 550 _ _Isognomon (Perna) 149 Prectinip=. (Tablets 691, 2525, 2526.) Pecten a. Meds kOe. aoe Sponpyuip#. (Tablets 692—701.) Spondylus isk oe 152 Pheatula ue iy 155 Ostreipe. (Tablets 702—74A.) Ostrea ng 156, 550 ANOMIADE. ( Tablets 745—780.) Placunanomia Rt te 164 Anomia ‘id nap 167 CLASS PTEROPODA. se bas 170 Vill. CONTENTS AGE CLASS GASTEROPODA. (Species 221—676, 692.) SUBCLASS OPISTHOBRANCHIATA. (Species 221—229, 692.) ORDER TECTIBRANCHIATA. Crticunipm®. (Tablets ala Cylichna x 170 Tornatina “ey 171 Bupiipz. Tablets 7 85—793. Bulla 2: xe 172 Haminea A ie 174, Purtinip&. (Tablet 2527.) Smaragdinella (Glauconella) 533 SUBCLASS PULMONATA. (Species 230—241.) ORDER GEOPHILA. (Species 230—234.) TESTACELLIDE. (Tablets 794, 795.) Glandina ae soa 174 Heutcipm. (Tablets 796—811.) Orthalicus (Bulimus) 176 ORDER LIMNOPHILA. (Species 235 238. ) Auricunipz (Tablets 812—814. ) Melampus (Conovulus) ie 178 Limneipe. (Tablets 815—832.) Aplexa (Physa)... PAN 179 Planorbis a 181 ORDER THALASSOPHILA. ( Sueeies 239—241.) SipHonarmaDE. (Tablets 833—867.) Siphonaria ... 181, 550 SUBCLASS PROSOBRANCHIATA. (Species 242—676.) ORDER HETEROPODA. (Species 242, 243.) TanruHinip®. (Tablets 868—878.) Tanthina ... 185,550 - ORDER LATERIBRANCHIATA. (Species 244—247.) Dentatiape. (Tablets 879—882.) Dentalium ... 188 ORDER SCUTIBRANCHIATA. ices 248—329.) Cuttonipm. (Zablets 883—907.) Lophyrus Len Ve 190 Tonicia a 193 Lepidopleurus ce .. 194, 550 Chiton my a 198 Acanthochites Ki abe 198 CONTENTS x. (Gasteropoda Scutibranchiata, cont.) PAGE. PateLiipm. (Tablets 908—944.) Patella Rl ct 199 Nacella Din hg 202 Acmmipm&. (Tablets 945—1016.) , Acemea (Tectura) te 202, 550, 551 Scutellina es a 210 Gapiniapm. (Tablets 1017—1023.) Gadinia iy ey 212 FissureLtuip®. (Tablets 1024—1080.) Fissurella ee BY 213 Glyphis.... of. 220, 551 Rimula aN Me 222 HALiorip#. Trocnipm. (TZablets 1081—1180.) Callopoma (Turbo) 2 223 Phasianella ... mh 224, Bankivia We 226 Uvanilla ( Imperator) 227 ‘irochus a OZ Le bok Omphalius sy 233, 551 Vitrinella Ds ane 236 ? Liotia B38 koe 248 Globulus (Rotella) ey 250 Kthala ina uh 250 Teinostoma 253 Neritipm. (Tablets 11811312. ye Nerita : us 255 Neritina We Cs 258, 551 ORDER PECTINIBRANCHIATA. (Species 330—676.) Susorper ROSTRIFERA. (Species 330—449.) Vanicoripm. (Tablets 1313—1315.) Vanicoro (Narica) 262 CALYPTREIDE. ie 1316—1461. t) Trochita 264 Galerus =a) ” 265 Crepidula iy mA 267 Crucibulum ... yy 286 Calyptrea 294, Caputipm. (Tablets 1462—1475. i Hipponyx ae 296 Capulus ne na 300 Xx. CONTENTS (Gasteropoda Rostrifera, cont.) PAGE. VerMETIDE. (Tablets 1476—1513.) Siphonium ... a 301 Aletes ey ae 301 Vermetus.... e 303 Bivonia ey i 305 Petaloconchus 308 Cauctpm. (Tablets 1514—1551. ) Cecum 312 TURRITELLID. (Tablets 1552—157 4,) Turritella ... ze 330, 552 CreritHiaD&. (Tablets 1575—14537.) Cerithium _... ee 333 Vertagus nt a 339 Triforis Ad ot 340 Cerithidea so oe 342 Lrrorinipm. (Tablets 1638—1703. ) Litorina oe = 346 Modulus a ee Sol 552 F ees he z 353 Isap 309 ices ” (Lablets 1704—1715. ) Rissoina a 356 Barleeia eS ee atite Ray Alvania ay me 359 Cingula ty ey 360 Hydrobia _... ne 360 JEFFREYSIADE. (TZablets 1716—1720.) Jeffreysia (Rissoella) ... 361 TRUNCATELLIDA. (Tablet 1721.) Truneatella ... _ 364, Pranaxipe (Tablets 1722—1732.) Planaxis me oe 364. Alaba ... a he 365 Ovutips. (Tablet 1733.) Ovula (Radius) ... 370 Crpreipm. (Tablets 1734—1812. ¥ Cypreea 371 Luponia ... oe 373 Aricia ‘op: ee 373 Trivia J 375 CANCELLARIADE. (Tablets oe Cancellaria 380 Strompipm. (Tablets 1821— ~1827 4) Strombus 381 CONTENTS Xi. ‘Gasteropoda Pectinibranchiata, cont.) PAGE. Sunorper TOXIFERA. (Species 450—483.) TrrEBRipm. (Tablets 1828—1878, 2515.) Terebra TOTOHA Be 384 Myurella 384, Subula 387 Huryta Oo: he 388 Prevrotomipe. (Zablets 1879—1915.) Pleurotoma ... et 390 Drillia 392, Clathurella ( Defrancia) 399 abe: 400 Cithar 401 ConIDz. ( Tablets 1916—1948. ) Conus 401 SuBORDER PR OBOSCIDIFERA. Seles 484—676. SonartmaDz. (Zublets 1949, 1950.) Torinia eh ve 407 PyrRaMIDELLIDEm. (Tablets 1951—2027.) . Obeliscus ae. i 409 Odostomia 410 Auriculina 413 Parthenia ... 413 Chrysallida 416 Chemnitzia 427 Dunkeria 433 EKulimella 436 Aclis 437 Eulima 438 Leiostraca ay xe 439 CreritHtopsipm. (Tablets 2028—2035.) Cerithiopsis 4A2 ScALARIADE. (Tablets 2 2036—2041. 1.) Sealaria 446 Cirsotrema 4AV Naticipm. (Zablets 2042—2061.} Natica : 4A8 Lunatia 451 Polinices AN “f 452 LAMELLARIADE. (Tablets ee 2063.) Lamellaria 453 Ficutipz. Ficula 453 Tritonips. (Tablets 2064—2072. vw - (Triton) Argobuccinum eo 454, Xil. CONTENTS (Gasteropoda Proboscidifera, cont.) PAGE. TURBINELLIDE. (Tablets 2073—2078.) . 456 Turbinella FascIoLARIADZ. (Lablets 20792090. ) Lathirus . [475] 457 Leucozonia [475 | 457 Fasciolaria 458 MiITRIN-. (Ranleterd 2091—2106. y Mitra 459 Strigatella .. 461 MaRGINELLIDE. (Tablets 2107—2109.) Marginella 461 Ona “(Labi 2110—2213. e) liva 463 Olivella 467 Acaronia 3. ee 472 Purruripe. (Tablets pe sat Purpura 474, Cuma 481 (Rapana) Rhizocheilus 484, Vitularia 485 Nitidella 487 BUcciNnIDz. (Tablets 2310—2365. ) Columbella 489 Metula 493 Nassinz. (Tablets 2366—2407.) Nassa a see 494, Pyrvriva. (Tablets 2408—2411.) Pyrula cis a 500 Moricipz. (Tablets 2412—2514.) Fusus ese tes 502 Cominella 505 Anachis 505 Strombina... 513 Pisania 513 Murex 518 Phyllonotus 521 Muricidea . 526 CLASS CEPHALOPODA. APPENDIX. Puitrpri’s Descriptions of Mazatlan Shells 534 Menxke’s First List and Descriptions of do. 536 Sf Second = do. do. 540 ADDITIONS and CoRRECTIONS CATALOGUE OF MAZATLAN MOLLUSCA. CLASS BRYOZOA. ir. Bryozoa; EKhrenberg, Corall. des Roth. Meeres, 153.—Jones An. Kingd. 107—117.— Owen Lect. 93—101.—Audouin & Milne- Edwards in Lam. An. s. Vert. ii. 104, 2de ed.—Carpenter Prine. Comp. Phys. ed. iv. pp. 50—68. Potyzoa, J. V. Thompson, Zool. Res. Mem. v. 92.—J. HE. Gray in Syn. B. M. 133.—Johnston’s Br. Zooph., 1. p. 253, ed. 2: v. note, p. 254.—Busk in Ann. Nat. Hist. 2nd Ser. vol. 10. _ p. 362. Motuuvscan Zoornyres s. Zoorpuyra Ascrprorpa, Johnst. in Mag. Zool. & Bot. i. 448. Cruiopracuiata, Parre in Phil. Trans. 1837. PoLyPEs TUNICIENS, VW. Edw. Mem. 16. Orper I. BRYOZOA INFUNDIBULATA. P. Gervais in Ann. des Sc. Nat. vii. 79.—Johnst. Br. Zooph. i. 255. Suporper I, CHEILOSTOMATA. Famity MEMBRANIPORIDA. Membraniporide, Busk, B. M. Cat. p. 55. Genus MEMBRANIPORA, Blaine. Menbranipora, Busk, B. WM. Cat. p. 56. 1. MEMBRANIPORA DENTICULATA, Busk, (n. s.) Areis cellularum rhomboideis ; apertur& interiort margine denticulato. The outline of the cells is usually distinctly defined by a narrow brown line. One or two rounded or triangular eminences (probably ovicells,) are visible on many of the cells in front July, 1855. b 2 MAZATLAN BRYOZOA and below. ‘This form bears considerable resemblance to Mem- branipora Savartii (Saviqny, Egypt. pl. 10; M. Lacroixu B. ©. Cat. p. 60, pl. 104, fig. 1.): but differs from it in several impor- tant respects ; among which may be noticed the narrow brown line surrounding the cells and clearly: defining one from the other; and the irregularly shaped branching denticles with which the margin of the interior calcareous aperture is fur- nished. Hab—Mazatlan ; on the shells of Imperator olivaceus, Imp. unguis and Anomia; Lzverpool Collection. Tablet 1 centains a group on Imperator. 2. Mempranipora Goruica, Rylands, ms. (n. s.) Areis cellularum elongatis, ovalibus; margine glabro, tenui ; ore elevato, suborbiculari, inferne late sinuato ; ceilularum superficie anteriort calcared depressd, punctatd, orificio magno utrinque perforato ; aviculariis magnis, immersis, trregulariter per polyzoarium sparsis. There is occasionally a short blunt spine or process on each side of the mouth, a character which also exists in M. Rozieri, Savigny, (B. M. Cat. p. 59, pl. 65, fig. 6,) a species to which the present exhibits in other respects considerable resemblance, and especially in the existence of the large opening on each side ~ of the front of the cell immediately below the mouth. The differences between the two, however, are sufficiently striking. In M. Rozieri the ovicell is large, superior, rounded, and carinate in front; whilst in M. gothica, as in M. calpensis, Bush, &e., this organ appears to be represented by one or two rounded eminences at the bottom of the cell in front. The large scat- tered avicularia also, are characteristic of the present form, as - well as its much larger size. The same species occurs on a pearl-oyster shell, for which T am indebted to Dr. J. E. Gray ; the habitat assigned to which is doubtfully given as the Persian Gulf. In M. M. Edwards’ Memoir Sur les E'schares, p. 17, pl. 12, fig. 13, a miocene fossil is described and figured, which bears considerable resemblance to the present ; it differs principally, so far as can be determined from the figure alone, in the thickened and granulated margin of the area. Hab.—Mazatlan: on Imperator olivaceus and unguis ; L’pool Col. Tablet 2 contains a group on Imperator.—3, a group detached. MAZATLAN BBYOZOA 3 Genus LEPRALIA, Johnston. Lepralia, B. M. Cat. p. 63. 3. Lepratia Aatrorusca, Rylands, ms. (n. s.) Cellulis elongatis, ovatis seu rhomboideis, lined tenui elevaté cinctis, superficie punctato ; ore suborbiculari, inferne sinuato, utrinque denticulato. General hue, blackish ; and even when the cells are more calcareous and on that account whiter, the dark interstitial line remains very evident. It is quite distinct from L. cucullata, (B. M. Cat. p. 81, pl. 96, fig. 4, 5,) also of a black colour, and. which occurs in the Mediterranean. Hab.—Mazatlan ; on Imperator olivaceus and" unguis, and on Anomia; L’pool Col. Tablet 4 contains 2 groups detached. 4. LEPRALIA TRISPINOSA, Johnst. B. M. Cat. p. 70, pl. 85; fig. 1, 2; pl. 98; pl. 102. fig. 2.— Johns. Br. Zooph. i. 324, ed. 2; pl. 57, f.7.—Couch Corn. Faun. iii. 118.—J. Macgillivray in Ann. § Mag. N. fist. 1x. 467. Discopora trispinosa, Johns. in Hd. Phil. Journ. xiii. 322. Berenicea trispinosa, Johns. in Trans. Newe. Soc. 11. 268. A single minute specimen only has occurred to my notice, . _but this is quite indistinguishable from the British form. Hab.—On shells from deep water, rare, Berwick Bay, Johnston. Coast of Cornwall, Peach.—On root of Laminaria digitata, near Aberdeen, Macgillivray.—Mazatlan ; on Imperator ; LT’ pool Col. Tablet 5 contains the group. 5. Lepratia Mazatnanica, Busk. (n. s.) Cellulis tmmersis, depressis, seu ventricoso-globosis ; swperficie punctato ; ore suborbiculari inferne late sinuato ; margine incras- sato, elevato ; aviculario unico (vel rare, duobus) laterali prope os. This form might easily be confounded with some varieties of L. unicornis, or L. Ballii. It is distinguished, however, by its reddish colour, and the elevation of the mouth together with its thickened margin. The single or sometimes double avicu- larium points outwards and upwards, and the mandible is pro- longed and acute. It is sometimes, but not frequently absent. Hab.—Mazatlan ; on Imp. olivaceus and unguis; L’pool Col. Tablet 6 contains a group on Imperator.—7, one detached. 4, - MAZATLAN BRYOZOA 6. LEPRALIA RostRATA, Busk, (n. s.) Cellulis immersis, superficie tuberculata seu granulata ; ore ~mmMerse, Margine supertori tnconspicuo ; margine inferiori pro- Funde suleato ; aviculario magno, sessili, armato. The lower or interior margin of the mouth in the fully formed. cells, is deeply grooved in the middle; and on one side of the sulcus is a strong, short, blunt, spinous process; on the other a comparatively large raised avicularium, which faces towards the suleus, and whose mandible is acute and points upwards and outwards. The surface of the cell is often beset with short raised spines or processes ; and these, projecting over the mouth of the cell below, give it the appearance of being furnished with several oral spines. Hab.—Mazatlan ; on Imperator unguis; L’pool Col. Tablet 8 contains a group on Imperator.—9, one on base of do. 7. LEPRALIA MARGINIPORA, Reuss. Fossil Polyp. d. Wiener Tertiar. Beck. p. 88, pl. 10, fig. 23. Cellulis ovatis, convexis seu subdepressis, immersis, asperulis, margine punctatis ; ore rotundo seu subelliptico ; margine sub- incrassato, singulo latere avicularium gerente. As the form appears precisely to resemble the tertiary species described and figured by Reuss, I have applied his name, and in great part employed his character. Hab.—Mazatlan ; on Imperator unguis; L’pool Col— Fossil, Vienna. Tablet 10 contains a group on hmperator. 8. LEPRALIA HIPPOCREPIS, Bush, (n. s.) Cellulis immersis, superficie punctatis ; ore suborbiculari sew elliptico ; margine superiori cellularum natu majorum, tnconspi- cuo, inferiori et laterali incrassato utrinque avicularium gerente. The peculiarly horse-shoe shaped mouth of the older cells, sufficiently distinguishes the present from the preceding species, to which, in the mouth alone of the younger cells, it bears some resemblance. Hab.—Mazatlan ; on Imperator olivaceus ; L’pool Col. Tablet 11 contains a group on Imperator. MAZATLAN BRYOZOA 3) 9. LepRaLia HUMILIs, Busk, (n. s.) Cellulis immersis, depressis seu complanatis, superficie obscure punctatis ; ore parvo rotundato, inferne subsinuato ; margine simplict, tenut. Hab.—Mazatlan ; on Imperator unguis ; L’pool Col. Tablet 12 contains a group on Imperator. 10. Leprania aADpPRESSA, Bush. Buskin B M. Cat. p. 82. The Mazatlan form differs from that from Chiloe in the absence or indistinetness of the radiating grooves. The mouth and shape of the cell agree perfectly. Hab.—Chiloe, 96 fm. on shell, Darwin.—Mazatlan ; on Colum- bella major, C. fuscata, and Pisania gemmata, not uncommon ; L’pool Col. Tablet 13 contains a group on Columbella. Famity IT. CELL EPORID. Busk, B. M. Cat. p. 85. Genus CELLEPORA, O. Fabr. Busk, B. M. Cat. p. 85. 11. CELLEPORA PAPILLEFORMIS, Busk, (n. s.) Cellulis sub-hexagonis, elevatis, superficie punctato ; ore sub- vrotundato utringue denticulato ; margine sinvplici, tenut, avicu- lariis sparsis, mandibulo triangulart. A well marked and distinct form, belonging to that subdivision of Cellepora in which the mouth is not armed with a projecting avicularium. The top of each cell projects in the form of a rounded mamillary eminence from a hexagonal area which defines the border of the cell. The cells are of very unequal sizes, and very irregularly disposed. It is of a brownish colour. Hab.—Mazailan ; on Imperator olivaceus ; L’pool Col. Tablet 14 contains a group on Imperator. 12. CELLEPORA cycLostoma, Busk. (n. s.) Cellulis suberectis, sew decwmbentibus, discretis, superficie punctato ; ore magno superne rotundato, inferne late sinuato ; cellularwum natu majorum margine valde elevato, incrassato, sub- inde dilatato, infundibuliformi, utrinque avicularium parvum gerente. 6 MAZATLAN BRYOZOA The wide, rounded or elliptical raised margin of the mouths of the distant cells gives the polyzoarium of the present species a very peculiar and well marked aspect. It is of a brownish hue, or white. Hab.—Mazatlan ; on Imperator unguis; L’pool Col. Tablet 15 contains a group on Imperator.—l6, a group de- ‘tached. Susorper II. CYCLOSTOMATA. FAMILY DISCOPORADA. Busk, (ms.) Genus DEFRANCIA, Bronn. 13. Derrancia IntRIcCATA, Busk, (n. s.) Disco valde irregulart ; irregulariter radiatun costulato ; ori- Jicits tubulorum, porisque interstitialibus equalibus magnitudine. The small irregular patches appear to be constituted by the confluence of several sets of coste with their corresponding interstices, each set radiating from a depressed central point. It differs from D. deformis Reuss, (L. c. p. 36, pl. 5, f. 24,) in the uniform size of the openings of the tubes in the coste and of the pores in the insterstices. HTab.— Mazatlan ; on Imperator unguis; L’pool Col. Tablet 17 contains a group on Imperator. —-—— Besides the above, there occur on some of the shells, indica- tions of other species, but in too imperfect a condition to allow of their determination. Among these perhaps the best marked is a species strongly resembling Cellepora pumicosa, Lin., a species of Lepralia, and of Tubulipora. CLASS TUNICATA. Omnia adhue ignota, MAZATLAN BIVALVES | CLASS PALLIOBRANCHIATA, Blamv. Brachiopoda, Cwv. Brachiopoda and Rudista (pars) Lam. Palliobranchiata, Blainv. Famity DISCINID/. Genus DISCINA, Lam. Discina, Lam. Orbicula, Sow. not Cuv. or Lam. 14. Disctina Cuminett, Brod. Orbicula Cumingii, Brod. in Proc. Zool. Soc. 1833, p. 125.— Brod. in Trans. Zool. Soc. 1. 143, pl. 23. f. 1— Mill. Syn. Test. Viv. p. 175.— Lam. An. sans Vert. Desh. ed. tert. 1. pt. 1. p. 118. no. 3.—Sow. Thes. Conch. p. 366. no. 4. pl. 73. f. 6.— D Orb. Voy. Amer. Merid. Moll. p.677—B. M. Cat. of D Orb. Shells, no. 786, p. 89. Discina Cumingii, Davidson's Class. of Brach. in Brit. Fos. Brach. vol. 1. p. 129. This shell is the Pacific analogue of D. striata, which pro- bably belongs to the Atlantic. Some specimens of each species are hard to distinguish from the other. D. Cumingii varies greatly in form, according to the place of its attachment, and is often extremely thin, and scarcely shelly. This is always the case with the lower valve, which has its disk of attachment subterminal, covered with a thin skin except at avery small chink. The upper valve is generally smooth near the apex, which is occasionally subcentral, afterwards closely set with radiating striz, more or less developed, and generally (not always) decussated by slightly raised lines of growth. Some- times nearly the whole of the upper valve is smooth and thin, as in levis. The lower valve generally displays only the con- centric lines of growth, but is occasionally decussated near the edge. It is sometimes so convex as to allow scarcely any space for the animal. Muscular impressions not so strongly marked as in D. striata. The young shells are often fringed round the edge, (with the remains of the cilia, Brod.) Colour, brownish yellow. The largest valve measures, long. °47, alt. *08 in. Hab.—Payta (Peru), St. Elena, Panama, attached to lower sides of stones in sandy mud at low water—6 fm.: Cuming.—Payta, Eeuador, St. Elena, D’ Orbigny.—Seas of Chili[?] and Peru, Deshayes.—Panama, common, under stones at low water, C. B. Adams. Mazatlan ; on Ostrea iridescens and Virginica, Chame, Pinne, Spondylus Lamarckii, Strombus galea, in um- bileal chink of Vitularia salebrosa ; rare, L’pool & Havre Coll. 8 MAZATLAN BIVALVES Tablet 18 contains 8 valves, very young, in test tube.—Tablet 19 contains 4 adult valyes.—Tablet 20 contains Ostrea Virginica, ‘with Chama ? spinosa attached, and 3 fine specimens of D. Cumingii in situ. One is removed from its nestling place be- tween the Chama and Oyster, and laid open to shew the inside. CLASS LAMELLIBRANCHIATA, Blainv. Conchifera: Lam. Phil. Zool. 1809; Ans. Vert. vy. 411, ed. 2, vi. 1.—Gray, Syn. B. M. 1840, 1842, p. 72; Proc. Zool. Soe. 1848, p. 183. Acephala Lamellibranchiata: Rang, Man. Moll. 272.—Forbes and Hanl. Br. Mol. i.55.—Clark, Moll. Test. Mar. Br. 23. Famity PHOLADIDA. Pholadide, Gray, P. Z. 8. Genus PHOLADIDEA, Twrt. Pholas, Lin. Lam. 15. PHoLADIDEA MELANURA, Sow. Pholas melanura, Proc. Zool. Soc. 1834, p. 70.—Sow. Thes. Conch. 1849, p. 499.— B. M. Cat. D’ Orb. Shells, no. 479, p. 56. This belongs to the same group of species as tridens, quadra, spathatula, and concamerata, which last represents it on the Californian coast. In its posterior cup-like appendages, it re- sembles Talona clausa from the Gambia. The shell is extremely thin, shewing inside a row of oblong tubercles impressed from without on the line separating the anterior and posterior por- tions, as well as the anterior ridges. These are closely set, strong, and waving; and passing over the medial depression at an angle slightly widening as the shell becomes adult, are continued, concentric and straight, ‘gradually fading as they approach the posterior extremity. This is covered with a thick epidermis, ending in a short double cup, which is bi-lobed outside and simple within. The adult closing of the valves is carried in a flat expansion round to the umbos. The largest specimen measures, with the cup, long. ‘9, lat. 1°85, alt. 8°6. Hab.—In hard clay and loose stones at low water, Monte Christi (Guayaquil), Cuming.—Ecuador, Monte Christi, D’ Orbigny. —Mazatlan; in company with P. acuminata, extremely rare ; L’pool Col. Tablet 21 contains the most characteristic (though a some- what imperfect) specimen. MAZATLAN BIVALVES 9 16. PHoLADIDEA ?curRTA, Sow. Pholas curta, Proc. Zool. Soc. 1834, p. 71.—B. M. Cat. D Orb. Shells, no. 482, p. 56. The only two specimens found are too imperfect to identify with accuracy. Though very small, they are both adult, and are known at once from the young of melanura by the extreme fineness of the anterior waved stiri, the posterior part scarcely shewing more than lines of growth. Dorsal plate shield-shaped, in two layers, hollow within, rather large and regular. Long. °28, lat. °34; shield ‘17 by °15. Hab.—Isle of Lions, Veragua, in soft stone at low water, Cum- ing.—Kcuador : Isle de los Leones, |? |D’ Orbigny.—Mazatlan, in Strombus galea, Havre Col. Tablet 22 contains 1 valve (the other being broken in extrac- tion) with its plate. Genus PARAPHOLAS, Conr. Parapholas, Conrad. sp. This genus, including Californica, Incii (Torres Str.), branchi- ata, calva, (acuminata,) and bisuleata (Woodw.) differs from Martesia (Leach) in having its cup lamin persistent and under- lapping one another. It further differs from Pholadidea in the large size of the umbonal plate, and the gaping in the ven- tral and dorsal margins, closed by plates in the adult shell. All yet known are from the Pacific. The Californian species is of large size, and makes a shelly tube for its siphons. 17. PARAPHOLAS CALVA, Gray, ms. Pholas calva Sow. in Proce. Zool. Soc. 1834, p. 69.—Thes. Conch. 1849, p. 493. Animal excavating a pear-shaped burrow in shell (or stone) which is perfectly smooth and circular transversely, so that the shell ‘(till it becomes adult) can move freely round in it. The orifice is subcircular, and rather large. As the animal continues its boring deeper, the swollen anterior portion becoming now posterior and therefore too large for the animal, which loves to have just room enough and no more, the vacant space is filled up with a lining (more or less thick according to the depth of the burrow) which is not an organic growth from the mantle, but appears to be nothing more than a sedimentary deposit in layers. Whether the burrow is in the purple or white portion of the Spondylus, the deposit is always dark grey. Jt may be detached as a tube from the cavity, and is often per- 10 MAZATLAN BIVALVES forated by other borers. The deposit is rarely seen in young shells, but is common in adolescent and ? universal in old speci- mens. At the bottom of the burrow is generally seen an irregu- lar mark projecting beyond the smooth surface of the hole, formed by the ?foot of the animal. Sometimes this is only a “sear, strongly resembling an irregular oval muscular impres- sion with an elevated marginal ridge from which it sinks back to a deep central linear depression, the whole strongly marked with concentric and radiating furrows.” (Darbishire). More often there is a sort of side chamber, or shoe, irregularly exca- vated in the shelly matrix, and not always in the same relative position, the surface of which is warty and very irregularly corrugated. This is generally filled with a black horny sub- stance, giving an animal smell when burnt, but not displaying any silicious particles. In very old specimens this excavation is often enormously developed, occasionally reaching up be- tween the grey deposit and the shelly matrix. Even in rather young shells this foot-chink is sometimes seen; and whenever the burrow reaches the inside of the Spondylus, the black substance is always first apparent. ? Does the foot make this lodgement as a fulerum, while the valves spin round and form the burrow: and after the adult valves can no longer move, ?does the foot amuse itself with forming these superfluous excavations. Shell, when extremely young, of xylophagoid shape, with the ventral portion undeveloped and the cup-lamine only existing as sight folds of the epidermis. Soon however two radiating lines become developed, and the ventral part rapidly increases. Throughout the younger portion of its life there is a very large dorsal as well as ventral gape. The anterior edge is marvelously thickened, ending in a stout knob, quite capable of aiding in bor- ing execution. In the single specimen found in a transition state, this knob is no longer prominent, and the anterior gape is par- tially filled with shell, not smooth as in the adult, but gradually carrying off the ribs of the thicker portion. Adult shell squarish or rounded anteriorly, short or length- ened, presenting all the intermediate forms between calva and acuminata of Sow.; fitting so tightly into its burrow that when dried it is often impossible to remove it without fracture, the umbonal plate being firmly adherent to the matrix. The epider- mis is thin on the anterior part; over the ventral part, folded in thick concentric layers, every 4 or 5 of which (varying in number) are as it were joined together along the posterior line into a series of tiles; and thence continued in a series of over- MAZATLAN BIVALVES 11 lapping horny lamine over the posterior portion. The snout is nearly round outside, displaying the gaping ends of the valves within, and a bi-partite lamina, rather rugose, between the two. The margin is entirely closed (except at the anterior part) with thick horny epidermis, strengthened ventrally by along narrow plate, not only filling up the gape of the young shell but projecting beyond the knob (now absorbed) into the anterior portion ; smooth, with a faint line in the middle: and dorsally by a thicker plate, with rather rounded projecting edges more or less swollen towards the umbos. These, with about a third of the surface of the valves, are covered with an irregularly shaped shield, smooth externally, encircling part of the dorsal plate, and with an internal, bi-partite, anterior lamina, fitting the valves. Between this shield and the hinge there is vacant room, but there appears no place of exit for the foot except at avery slight anterior chink, which seem to be all that the stretching power of the integuments can allow. The markings within vary considerably, the thick anterior ridge being often quite absorbed, and the hinge apophyses irregular. See a very full account of the animals of British Pholadide, and the relations between lamellata and papyracea of Turton, in Clark’s Moll. Test. Mar. Brit. p. 169—212. The following are measures of different specimens :—* Largest (acuminate) Long. °99 Lat. 1°93 Alt. .98 Shorter form * "81 1°45 “78 Smallest adult 95) 67 34, Smallest jun. "04, 06 P04 Hab.—Adult in Spondyli, 12 fm., Isle of Perico in Panama Bay ; jun. in hard stones at low water, zd. ;+ Cuming.—Mazat- lan: abundant in Spondylus Lamarckii: also in ?primitive (not limestone) rock to which the Spondyli are attached : 2 young specimens in Chame, and 1 in Strombus galea: Ppool § Havre Coll. ? Tablet 23 contains 8 valves very young.—24, 9 young speci- mens varying in size and acumination.—25, a young specimen with a part of its own burrow, in the tooth of a Spondylus, * In this family, and in Gastrochenide, the length was measured straight across, not to the middle of the ventral margin. t This is the accurate statement in the Proc. Z. 8.: in the Thes. Conch., it is given as ‘‘collected by Mr, Cuming in very hard stone at low water in Panama Bay ;” making it appear that all the specimens were thus collected, whereas the adults were found in Spondyli, 12 fm. deep. Similarly careless transcripts are not uncommon in the Monographs, I MAZATLAN BIVALVES shewing the grey lining and part of the pedal chink.—26, the adolescent specimen.—27, 6 adult specimens shewing various peculiarities of growth.—28, a small adult specimen in situ, with a thick irregular lining: another specimen remains en- tombed.—29, an adult with part of its burrow, shewing the stratified nature of the lining: the anterior portion of the shield curiously deformed.—30, a piece of Spondylus, with 3 young specimens in situ, and several burrows, shewing the stratified lining, and the pedal excavations reaching the inside of the shell, to the evident annoyance of the Spondylus, which has protected itself against one of its enemies by a protuberance ‘7 across, and *23 high.—31, a large piece of Spondylus with various burrows: a large one of calva, with enormous foot chink: a smaller one in the hinge tooth: two others with small foot marks: a burrow of ?Lithodomus encased from an old hole into which it had penetrated: a singularly twisted burrow of Gastrochena, bent nearly double, &c.—32, fragments of the horny ?foot.—33, fragments of the grey deposit.—34, fragments shewing hinge structure.—35, fragments illustrating the cup- laminze.—36, portions of the umbonal plate.—37, portions of the dorsal and ventral plates. 18. PARAPHOLAS ACUMINATA, Sow. Pholas acuminata, Proc. Zool. Soc. 1834, p. 70.—Sow. Thes. Conch. 1849, p. 492. The author of this species distinguishes it from calva by the shape of the lamine and posterior portion, which are variable in both forms; and by the character of the umbonal shield. This last is the only constant character of difference. It is not only smaller, not projecting beyond the dorsal plate ; (which is not the result of age, being found in all the specimens ;) but, in all the specimens allowing of observation, it is turned-in all round, instead of at the anterior portion only as in calva. The external surface also is generally rougher, and the posterior gape smaller, not displaying the bipartite lamine so clearly. Still, as the shells exactly agree in all other respects, it is pro- bable that these differences only result from changes in situation. All the calvee were taken out of Spondylus: all the acumi- nate were sent loose; and from their extremely perfect con- dition were probably extracted from clay or wood. If the latter, the irregularities of the decaying timber might cause the roughening of the plate-surface. The original specimens of acuminata however were taken out of argillaceous limestone. The largest specimen measures long. °8, lat. 1°54, alt. 77. MAZATLAN BIVALVES 13 Hiab.—Panama, in limestone rocks at low water, Cuming.— Mazatlan ; not uncommon ; L’pool Col. Tablet 38 contains 3 normal specimens.—39, 3 do. distorted.— 40, 2 do. shewing inside, and plates. Genus MARTESIA, Leach. Differing from Pholadidea in the large development of the accessory plates; from Parapholas in the cups not being per- sistent. 19. MaRTEsiaA INTERCALATA, 7. S. M. t. parvé, subglobosd, in duas partes divisd; parte anteriore tenuissime concentrice striata, radiis longitudinalibus subobsoletis vie undatéi; in juntore maxime hiante, margine solido ; um adultd secretione semi-corned clausd : parte posticd sublevi, epiderinide copiose indutd, margine rotundato; um- bonibus testd reflexa adherente celatis ; clypeo pyriforme, parvo, solido, inter secretiones valvarum intercalante; partibus ventrali et dorsali laminis semi-corneis, brevibus, a calyce repulsis ; calyce plano, brevi, simplici, extante. The species is named from the remarkable way in which the umbonal shield pushes itself in anteriorly between the project- ing portions of the closed valves ; and in which the cup, which pouts out from the otherwise rounded extremity, pushes itself in between the anterior and posterior plates, cleaving them and thrusting them back. Mr. Hanley was fortunate enough to find two specimens burrowing in Spondylus, of which the larger has not yet closed the anterior portion, but the smaller is adult. The shield does not fold round the dorsal plate. The whole dorsal and posterior part has a thickened raised margin, pro- bably epidermal. The largest (adolescent) specimen measures long. 34, lat. °35, alt. °33. The cup in the smaller specimen measures ‘06. Hab—Mazatlan ; in Spondylus Lamarckii, extremely rare ; Havre Col. Tablet 41 contains various magnified sketches of the two specimens in Mr. Hanley’s collection. IpitEs A curious little fragment, unfortunately too imperfect for identification, which may belong to a Pholad, but is certainly distinct from any of the foregoing. Shell with a strong, irre- Aug. 1855. ¢ 14 MAZATLAN BIVALVES gularly curved tooth, deeply channeled on the convex side. appressed to the umbo and projecting considerably above the margin of the valve. No process on the hinge as in Pholas, and apparently with groove for external ligament. Outside oval, smooth near umbo, afterwards with slight concentric rounded ribs and very slight radiating furrows. Tablet 42 contains the fragment, and a magnified sketch. Famity GASTROCHZANIDZ. Genus GASTROCH ZENA, Spengler. 21. GASTROCHENA TRUNCATA, Sow. Proc. Zool. Soc. 1834, p. 21. Animal excavating a smooth oval chamber at the end ofa flattened narrow gallery, occasionally five times as long as the chamber itself.* The gallery is straight, variously bent, or even suddenly recurved at a considerable angle, according to circumstances. It is always lined with a shelly coat, not evidently different from the shelly matrix, but separable from it. The interior of the siphon gallery is more or less rugose, and towards the extremity is nearly bipartite. The presence of these creatures may always be detected by the 8-shaped holes they make; but there is no clue by which the probable place of their abode ‘can be ascertained. When they make a sudden turn, in consequence of some knowledge .of an approaching stranger even at a distance, they fill their discarded burrow with shelly lining. The English species has no objec- tion to burrowing through the graves of departed brethren, carrying its tube across them: this was not noticed in any. Mazatlan specimen. A ? foot mark is often observed opposite the anterior gape, but never so large as in Parapholas: occa- sionally in the adolescent shell, a chink is seen in a downward direction, filled with the black horny substance. The valves have free room to open widely in the cavity. The form varies, even in the young shell, and often, both in outline and markings, approaches ovata. It may be known at once however by the great peculiarity of the hinge; in which the “small, spathulate lamina” which Forbes & Hanl. have record- ed in their generic character, though scarcely observable in G. modiolina, assumes dimensions which almost entitle it and similar species to subgeneric rank. Umbos very near anterior gape: an indistinct diagonal line beyond which the concentric * Mr, Darbishire found one which measured 4°5in, exclusive of the cell. MAZATLAN BIVALVES ty striz are coarser and more irregular. This (posterior) portion of the shell is covered with very copious epidermis, in wrinkled. folds, as in Saxicava rugosa. Ligament long. The young shell has projecting umbos, and often serrated edges to the anterior gape. The largest specimen measures long. 57, Jat.1°17, alt. 57. The smallest valve, long. ‘02, lat. °05. Hab.—In Spondyli, Isle of Perico, Panama, Cuming.— Mazat- lan; not uncommon in Spondylus Lamarcki, very rare in Chame, Patella Mexicana, and in Imperator olivaceus and unguis ; L’pool & Havre Coll.* , Tablet 43 contains 6 valves very young, and 3 pairs adolescent. 44, Young specimen, piercing the apex of Imperator unguis. 45, do. Imp. olivaceus, with Bryozoa, &c. attached.—46. Young specimen in situ in Imp. olivaceus, with another younger, coter- minal.—47. Young specimen in Imp. olivaceus, with tube some- what projecting, which is unusual at Mazatlan.—48. I. olivaceus broken across, and shewing 5 specimens of G. truncata, and one Lithodomus caudigerus, invading the Imperator’s liver chamber. —49. Adolescent specimen in situ in fragment of Spondylus, with the tube laid bare, and the pedal chink and deposit. Also portions of several other tubes of Gastrochena, Lithodomus and Petricola.—50, 3 adult specimens varying in outline, of which one displays a pearl formed near the hinge, another a lamina cutting off a large part of the anterior end, as often happens in large aged fossil Saxicave.—5l. Fragment of Spondylus, displaying hole of G. truncata, which, having approached a Lithodomus too closely, has turned round, filling the vacant space with shelly matter.—52. Siphon pipe laid bare, by the decay of the worm-eaten Spondylus around: also bur- rows of Lithodomus plumula and Parapholas calva.—3, Pipes and thick lining of 3 Gastrochene in Patella Mexicana: the two siphons in one are ail-but separated at the extremity.— 54, 2 pipe-ends from Spondylus.—55, Fragments of shelly lining. 22. GASTROCHENA OVATA, Sow, Proc. Zool. Soc. 1834, p. 21. Burrow not differing perceptibly from that of G. truncata. Shell, when fresh, of a delicate lilac tinge, with sharp elegantly bent concentric ridges following the margin, closer at the an- * In the Bristol Institution is a Tablet marked G. cuneiformis, from the West Indies, Mr. Priske, containing 2 specimens ; of which one I was unable to separ- ate from G. ovata, the other (in its burrow) from G. truncata. Mr. Hanley states, from the examination of a collection made by M. Bean in Guadaloupe, ra sent to him by M, Petit, that several species of borers are common to the wo oceans. 6 MAZATLAN BIVALVES terior part. Epidermis not conspicuous. Lunular portion deeply impressed : umbos distant from margin. Hinge without spath- ulate lamina: mantle marks rugose. More or less elongated, approaching sometimes the more ovate forms of truncata, especi- ally in the young shells, but distinguished at once by the hinge. The anterior margin in the young shells is generally serrated, like Pholas, more strongly than in truncata. Anterior por- tion either more or less than one-fifth of the entire length. The largest specimen measures Jong. °76, lat. 1°1, alt. 6°2. Smallest, Jong. *04, lat. 08. Hab.—\sle of Perico (Bay of Panama) and Isle of Plata, Cwm- ing.—Mazatlan ; inSpondylus Lamarcki, very rare; L’poo/ & Havre Coll. Tablet 56, 1 valve and 2 pairs very young.—57, young speci- men in situ.—58, 2 adult specimens; one lilac, fresh; the other white, large, dead.—59, fragments of shelly lining. Famity SAXICAVIDA. Genus SAXICAVA, Bellevue. 23. SAXICAVA arctica, Lin. (For the synonyms, both as to genus and species, of this Protean shell, see B. M. Cat. Brit. An. Part VIL. pp. 86—89.) ?=Saxicava solida, Sow. Proc. Zool. Soc. 1834, p.88: .D’ Orb. Voy. v. 521. ?=Saxicava Cordieri, Gould. ms—Mazatlan, Lieut. Green. This shell is named on the authority of R. M’Andrew, Esq. whose practical acquaintance with the forms it assumes both in Arctic and subtropical regions renders his opinion of weight. According to Hanley, Menke and Gould, it is a distinct species. I cannot separate some forms of it from solida. The creature seems to take delight in distorting itself, not thinking it. neces- sary to lodge in an uneven cavity for that purpose. It seldom (if ever) bores, being found in cavities of Lithodomus &c. The young shells are just as variable as the old ones, sometimes assuming the characters of S. rugosa or the form of Sphenia Binghami, but generally displaying the narrow, anteriorly trun- cate, bi-tuberculate character of 8. arctica. It rarely takes the genuine Hiatella form. Ligament of variable length, generally rather short. Valves capable of opening widely, though rarely MAZATLAN BIVALVES Ly) m a position to do so. Hinge teeth, 1 in each valve, rarely seen in adult. Largest specimen measures long. ‘63, lat. 1°17, alt. °47, A broad flat sp. es be AYR SONOS, takes jc 4m A long narrow one 5 FAD Eee) eA OGL Waar 2) Smallest "3 5 OZ Na petri OAe to ee Oils Hab.—According to Forbes, Atlantic Ocean, Boreal Seas, Africa, China, Australia.—Canaries, Webb & Berthelot, B. M. Cat. Can. Moll. p. 22, no. 195.—New Zealand, Capt. Stokes, B. M.—S. solida: Clefts of rocks, 18 fm. St. Elena, Cuming : Peru, Lima, Callao, D’ Orbigny, B. M. Cat. p. 58, no. 510.— S. distorta, Say, Rhode Is. Jay.—S. Pholadis, Sea of Okotsk, Middendorf.—Mazatlan ; in Spondylus Lamarckii, nestling in crevices and burrows, also in Chame and Patella Mexicana, very rare adult, not common jun.; L’pool & Havre Coll. Fossil, Crag, &c. ; very large in the pleistocene beds at Ud- devalla, Sweden, R. D. D. Tablet 60, 6 young valves.—61, 1 valve and 6 pairs various ages and shapes.—62, 1 specimen bored into, and the valves cemented open by tube of borer: also 2 fragments to shew ligament.—63, A young specimen in hole of Lithodomus cau- digerus in Imperator unguis.—64, A specimen in situ in a Ver- metus, off back of Spondylus. Famity PETRICOLID. Genus PETRICOLA, Zam. 24. PETRICOLA RoBUSTA, Sow. Proe. Zool. Soc. 1834, p. 47.—Sow. Thes. Conch. part xv. p. 775, no. 14; pl. elxvi. f. 16, 17.—Miiller, Syn. Moll. p. 229, no. 9.— Philippi in Zeit. fir Malac. 1848, p. 163, no. 33, quasi sp. nov.: edidit Desh. in B. WM. Cat. Veneride, &e. p. 210, no. 10. ?=P. bulbosa, Gowld’s plates, ms. The name of this shell, which was well described by Sow. in 1834, was appropriated by Philippi in his 37d Century of new shells for a supposed new species ; which turns out fortunately to bea small specimen of Sow.’s species, and thus confusion of synonymy is unexpectedly avoided. Deshayes has unfortu- 1g MAZATLAN BIVALVES nately copied this description into his Cat. Ven. B. M., mstead of the original one. The young is generally (so Phil.) “sub- elobosa, alba,” and occasionally shews the radiating ribs “pos- tice distantibus’”’; the bifidity of the anterior tooth in the left valve is rarely seen in the adult. When extremely young, the shell is irregularly rugose, but not shagreened : the apex is then moderately prominent: the rugosities soon fall into regular: ribs dividing between the posterior and ventral parts; the interspaces are finely rugose. Very soon the apex disappears, and.a large space round becomes eroded. The shell which has previously been white, assumes various shades of orange, lilac and chocolate, developing at last into a lustrous brown, especi- ally at the muscular impressions. Meanwhile the characteristic concave decussating strie appear between the ribs; and on the posterior ribs (which are generally closer than the ventral but not so close as the anterior ones) are gathered up into knobs. The anterior ventral part is generally much swollen, often with a coneave margin between that and the posterior end, which is not unfrequently much produced, flattened, and even bent up- wards. The short, semi-internal ligament (somewhat resembling Ungulina) is turned up spirally round the umbos, as inChame, &e. The burrow is shaped as the shell, with a rising corresponding with its posterior ventral depression, and without any siphon gallery. The opening is oval, irregular, and always exposes to view the extremities of both valves. Mr. Darbishire has one fourth of a Spondylus valve, with no fewer than eleven Petricole projecting their extremities. The interior of the burrow is irregular and rough. One of the Chama, here- inafter enumerated, displays a Petricola, which, having bored through the Chama and come to the rock, preferred flat- tening its own valve to undertaking the unexpected labour. This creature, having no power to move round in its hole, is frequently bored into by its neighbours. A pedal scar is occa- sionally seen towards the anterior end, sometimes deep, with dried horny substance as in Parapholas. The largest’ specimen measures long. 87, lat. 1°22, alt. °73, The most oval he Fla 63, hee AO oe en Oe, The smallest " ee OOF ane: goa. ee Hab.—tIn rocks, 6—11 fm., Panama and Isle Muerte, Cuming.— Jun. in Avicula margaritifera, Panama, #. B. Philippi — Mazatlan: in Spondylus Lamarkii, not uncommon: very yare in Chama. Very young shells are rarely met with: MAZATLAN BIVALVES 19 perhaps from living near the outside, and therefore being _ easily washed out; L’pool & Havre Coll.* Tablet 65, 4 young valves.—66, 2 pairs, 2 valves, adolescent.— 67, 2 pairs, adult.—68, 2 pairs bored into and distorted.—69, specimens of dried foot.—A burrow may be seen in ?36, and a specimen in situ among the Chame. 25. PeTRICOLA VENTRICOSA, Desh. Proc. Zool. Soc. 1853, Pubi—B. M. Cat. Ven. p. 214, no. 22. = (teste Sow.) P. denticulata, Sow. Proc. Zool. Soc., 1834, p. 46.— . Sow. Thes. Conch. part xv. p. 773, pl. elxvi. f. 6,7.—B. M. Cat. D’ Orb. Moll. p. 64, no. 564.—B. M. Cat. Ven., p. 213. no. 21. This shell agrees with the description of P. ventricosa better than with that of P. denticulata, and must rank with that species if they prove distinct. If they are identical, as. Sow. supposes, his name, though not so expressive, has priority. It takes poe one elongated and abbreviated forms. Long. ‘26, lat. °36, alt. °25. Hab.—(P. denticulata) Payta (Peru) in hard clay and stones at low water, Cuming.—Arica, D’ Orbigny.—(Var. abbreviata) Isle Plata, Cuwming.—Payta D’Orbigny.—(P. ventricosa) Gulf of California, Mus. Cuming.—Mazatlan: burrowing in Strombus galea, extremely rare, Havre Col.—Received with other shells from the West Indies, P. P. C. Tablet 70 contains 2 opposite valves. 26. PEetR1coLa —————, sp. tnd. Tablet 71 contains a rugose fragment, apparently not identi- cal with any published species from the W. American coast. Hab.—Mazatlan : in Spondylus Lamarckii: L’pool Col. * I strongly suspect that this species is also found on the W. African coast. I have a valve, received from the Bristol Institution where it had been before they had a single shell from the West Coast of America that I know of, and before Cuming’s discoveries there. At that time there was plenty of trade between Bristol and Africa; and I believe the species came out of Ostrea iridescens of which they had a large stock, Vide remarks on {that sp. and Placunanomia, If P. typica, Sow. Thes. Conch. No. 13. does not differ from robusta more than is there stated, it is probably the same species, from St, Thomas, W. Indies, 20 MAZATLAN BIVALVES Genus RUPELLARIA, Bellevue. Rupellaria, Flewriau de Bellevue, 1802, Bullet. Soc. Philom. nv. 62.—Philippi, Handb. d. Conch. § Mal. in loco. Gastrana, Schum. 1817. Venerupis, Lam. 1818.—Desh. B. M. Cat. Ven. p. 189. 27. RUPELLARIA LINGUA-FELIS, 2. S. V. t. subcylindricd, alba, tenuissime et dense granulosa, sub- diaphand; granulis irregulariter confertis, lineis radiantibus confluentibus ; circa wmbones laevigata, liris concentricis inter- ruptad ; strias incrementi nonnunquam monstrante ; lunula in- distinctd; wmbonibus prominentibus ; intus politd, margine plana; impressiones nusculares viz monstrante, sinu palli magno, circulart ; dentibus 3—2, quarum una bifida; nymphis et liga- mento parvis; dentibus et nymphis supra lineam cardinalem intus prominentibus. Shell in shape like P. mirabilis, Desh., which represents it on the Californian coast; but recognized at once by its surface which presents, under the microscope, most delicate granula- tions somewhat like Tellina lingua-felis, whence its name. Smallest specimen measures long. ‘025, lat. 03, alt. *02, Largest 9 ” 33 2BP 16, 99 ‘09. Hab.—Mazatlan ; in Chame and Spondylus es cku, nestling in burrows, rare ; T’pool & Havre Coll. Tablet 72 are 5 specimens in various stages of growth. 28. RUPELLARIA EXARATA, 7. s. Vt. forma “ Lingue-felis” simili, umbonibusque ut in specie ili: sed radiatim tenue suleatd, albicante, rufo-fulvo macu- lata: fortiori, nec intus politi: dentibus 3-3, quarum una bifida, extantibus : epidermide tenut, fusca. Shell in size and shape like V. lingua-felis, but wanting the granulose texture, and covered (except at the umbos, which are concentrically striated) with very fine rather irregular radiating ribs, as in Petricola, interrupted occasionally by lines of growth. Colour whitish, stained with chocolate. Hinge teeth projecting upwards, not sideways as in the last. Pallial sinus large, well rounded. These shells have the general appearance of Naranio, Gray. MAZATLAN BIVALVES 21 Smallest specimen, long. ‘018, Jat. ‘03, alt. ‘015, Largest’ i Lom Shee OR Pipe] a be) Hab.—Mazatlan; a small colony were found nestled, and greatly incommoding each other, in empty Balani on Murex princeps: Havre Col. Tablet 73 contains 1 specimen in situ, in Balanus ; 3 others of different ages. 29. RUPELLARIA —, sp. ind. Tablet 74 contains a fragment resembling R. foliacea, Desh. Mazatlan ; with strong radiating ribs crossed by erect and beau- tifully undulated lamine. The sculpture smoothes off at the hinge margin. Hab.—Mazatlan; from the back of a Spondylus Lamarcki ; LP’pool Col. Famity CORBULID. Genus CORBULA, Brug. 30. CORBULA BICARINATA, Sow. Proc. Zool. Soc. 1833, p. 35.—Miull. Syn. Test. Viv. p. 229.— Rve. Conch. Ic. 1844, pl. 3. f. 23 —Hanl. in Woods Suppl. Ind. Test. pl. 12, f. 31.—Hanl. Desecr. Cat. p. 46.—B. M. Cat. D Orb. Moll. p. 70, no. 619. Shell extremely swollen, the valves nearly equal, sometimes one a little overlapping the other at the posterior ventral margin. Epidermis thin over the body, thick over the margins of the valves. Irregularly concentrically striated over the surface, very finely between the posterior keels: umbonal portion smooth. Within, ligament affixed to the smaller tooth: pos- terior muscular scar rounded, on a projecting support; a smaller one behind: anterior scar oblong. Pallial line simple. In the 3 specimens which alone I have had an opportunity of examining, which are quite fresh, I cannot detect any pallial sinus. Those who have plenty of Corbule would do well to examine their interiors, which are not generally noticed in the descriptions. They are either very rare at Mazatlan, or have escaped detection, scarcely a dozen specimens having been found of all the species. Long. 2°7, lat. °36, alt. °28. Hab.—In sandy mud, 7—17 fm., Panama, Real Llejos, Caraccas, St. Elena, Cawming.—W est Columbia, Hanley, Jay.—Ecuador, 22 MAZATLAN BIVALVES S. Elena, D’Orbigny.—Panama, common, C. B. Adams.— Mazatlan ; extremely rare; L’pool Col. Tablet 75 contains 1 specimen, laid open. 31. CORBULA BIRADIATA, Sow. Proc. Zool. Soc. 1833, p. 35.— Mull. Syn. Test. Viv. p. 230.— Fve. Conch. Ic. pl. 1, f.3.—Hanl. Suppl. Wood's Ind. Test. pl. 10. f. 51—Hanl: Deser. Cat.-p. 47.—B. M. Cat. D’ Orb. Moll. p. 70. no. 620. Shell with valves nearly equal, ventral margin flattened, posteriorly rather widely overlapping. Epidermis scarcely visible except at the margin, where it is, as usual, thick. Within, purplish white, ligament attached to larger tooth. Posterior muscular scar strongly marked, partly projecting, partly indent- ed, subcircular, with the little one behind coalescent. Anterior scar pear-shaped. Pallial line irregular; sinus very small. Long. °33, lat.°52, alt. °26. Hab.—Mud and sand, 3-6 fms., Chiriqui: 7 fm., in Bay of Came cas: Cuming. — Ecuador; Chiriqui: D Orbigny.—W .Columbia, Jay.—Panama, very rare, C. B. Adams.—Gulf of California, Mus. Cuming.—Mazatlan ; extremely rare: ZL’pool Col. Tablet 76 contains the only specimen found, in extremely fine condition, flattened. 32. CORBULA PUSTULOSA, 2. 5. C. t. parva, alba, obesd, solidd, postice producta, truncata, antice rotundatd, ab umbonibus postice subangulata ; valva minore plus minusve tnclausd, maxime in margine ventrali ad posticwn decurrente, arcuata: valvis concentrice liratis, liris irregularibus, subrotundatis : epidermide tenwi, ad marginem erassd:: Lineis exillimis radiantibus pustularum minimarum repletis: umbonibus levigatis. Shell small, white, subglobose, produced posteriorly, with the valves overlapping, bent at the posterior end of the ventral margin; with irregular, somewhat rounded concentric ridges, crossed by the finest radiating lines, which under the microscope are found to consist of rows of minute pustules, probably formed in the epidermis, which is extremely thin over the body of the shell, coarse round the margin, and at the posterior side, which is rather angulated. Mr. Cuming’s specimen measures Jong. °16, lat. °24, alt. °14, The Mazatlan specimen a ed eh ees “11. MAZATLAN BIVALVES 23 Hab.—Panama and St. Blas, 33 fm. R. B. Hinds, Mus. Cum- ing.—Mazatlan: one small pair nestling in Spondylus, and 1 valve in Chama, L’pool Col. There is no doubt that the Mazatlan shell is the same as Mr. Cuming’s beautiful specimen, hitherto undescribed. Tablet 77 contains the perfect specimen ; I reserve the valve. 33. CORBULA PovuLATA, Sow. Proc. Zool. Soc. 1833, p. 35, 36.—Mill. Syn. Test. Viv. p. 230.— Rve. Conch. Ic. pl. 1. £.7.—Hanl. in Suppl. Wood’s Ind. Test. pl. 10, f. 52.—Hanl. Deser. Cat. p. 47.—B. M. Cat. D’ Ori. _ Moll. p. 70, no. 622. Tablet 78 contains 1 flat dead valve of regular oval shape slightly produced anteriorly, and very finely striated concen- trically, which may belong to this species. Hab.—In sandy mud, 7—17 fm. Xipixapi, and Bays of Montijo and Caraccas, Cuming.*—EKcuador: Xipixapi, D’ Orbigny.— Taboga, very rare but large, C. B. Adams.—Mazatlan ; one valve, L’pool Col. 34. CorBULA——— , sp. ind. Tablet 79 contains a fragment of what must be when perfect a most beautiful and remarkable species. It is extremely thin, white, translucent, with a very sharp diagonal posterior keel, and another close to the margin. Umbos very near the anterior end. Shell smooth near the umbos; afterwards with waved concentric ridges; posterior part with deep pits at a sharp angle with the ridges. The whole shell with radiating rows of dots (probably epidermal) as in C. pustulosa. Inside a stout, - somewhat conical tooth in each valve, with corresponding pit. Interior surface very finely rugose. Mr. Hanley found a much more perfect specimen, which was most unfortunately crushed in transmission by the post. Hab.—Mazatlan ; from Spondylus Lamarckii ; L’pool & Havre Coll. es * Mr. Reeve further states ‘‘A few odd valves of this species were found by Mr. Cuming on the sands at Real Llejos and Mazatlan.” In reference however to this last locality, Mr. Cuming states that his extreme point north, along the West American coast, was Conchagua, Bay of St. Carlos (or Fonseca) : about 13° N. L. In all cases therefore where he is cited as the original collector at places north of this, the authority must be regarded as ** Museum Cuming,” DA MAZATLAN BIVALVES Genus SPHENIA, Turton. For Monograph of this genus, with amended generic characters, see A. Adams in Proc. Zool. Soc. 1850, p. 86. See also Forbes & Hanl. Br. Mol. vol. 1. p. 189—193 :—Clark Br. Mar. Test. Moll. p. 150. 30. SPHENIA FRAGILIS, 2. s, S. animali in eryptis latibulante, erge varie distorto ; testa parva, tenui, subnacred, via rugose striata ; epidermide fusco- virente copiose indutd, rugarum increscentium concentricarum plend, postice in siphone longd porrecta: parte posticd plus minusve subcarinatd ; valva sinistra dente ligamentum ferente. plus minusve seu prolongatd seu extante; dextra alveo conveniente. nonnunquam denticulo subextante: vinpressionibus muscularibus subrotundatis, sinu pallit lato, rotundato, haud alto. Tt is surprising how much of the very minute description of S. Binghami given in Forbes & Hanl. Br. Moll. i. 191-2, applies exactly to individuals of this species. Indeed, if young speci- mens of the two were mixed together, I should hardly know any sufficient ground of specific distinction, except in the texture which is more nacreous, and the pallial sinus which is broad, though shallow. The young shells can sometimes be told from those of Saxicava arctica only by the hinge, as in Binghami: and there is often seen the little denticle by the hgament pit noticed by Turton, not Hanley, and conspicuous in young shells of Spheenia Binghami in my possession, nestling in cre- vices of limestone dredged off Weymouth. Like other nestlers (anlike the true borers, which are moderately constant in form) it is extremely irregular. Many well characterized species might be made out of extreme forms ; but unfortunately for the lovers of multiplication, individuals were sufficiently numerous to supply many connecting links. The normal state appears to be not very inequilateral and tolerably well rounded : the shell is then shaped somewhat like Psammobia: but it is generally more or less produced, when the posterior portion becomes marked off by an angle, in very long specimens amounting toa keel, sometimes with a trace ofa double one. When it lives in dead Balani &c., 1t becomes very short, inflated and gibbous, resembling Corbula or sometimes Nexra. The ligamental plate then becomes narrow, projecting and sinuated, more like the tooth of Mya. These variations are seen in the MAZATLAN BIVALVES As) young as much as in the adult shells. A very small specimen was found to contain a minute young one. Specimens as broad as "Zin. are very uncommon. One specimen was found having its siphon pipe projecting nearly half the breadth beyond the shell. Smallest specimen measures cong. ‘02, lat. °03 alt. °O15. HKlongated +) +9 bE) Us ’ 99 1, 33 "02. Oval 59 23 99 ‘2s 99 "26, 33 14. Largest by 7 ie aL Ssnee yh iictlye mana te Ag Hab.—Mazatlan: inhabitme the burrows of worms and Mol- lusks in Chame and Spondylus Lamarclai; also in dead Balani on Strombus galea; not uncommon; L’pool & Havre Coll. Tablet 80 contains 22 valves and 1 pair, jun. of various shapes.—8l, a pair of regular shape with young nullipore grow- ing on; pair with long siphon pipe; valve with internal lamina : 5 broken valves shewing hinge structure, &¢.—82, the largest specimen, from hole of Lithodomus caudigerus in Strombus galea; a Balanus with oval Spheenia taken from within. . We insert here a notice of a unique sheli deseribed by A. Adams in the An. Nat. Hist. 1854, p. 418, under the name of Tyleria fragilis. Though named in honour of Mr. Tyler, he had it in his possession a considerable time without knowing of any thing remarkable attending it. I have taken several journeys to Liverpool and made enquiries in London, in hopes of seeing it, without success: but, as evidence that it is not mythical, I deposit, on Tablet 83, drawings made by Mr. Sowerby and most kindly placed at my disposal by H. Adams, Esq. It is possible that it is a deformed shell. I have occasion- ally noticed valves of Sph. fragilis with a tendency towards the same crenation at the posterior end, apparently through irritation of sand, &c.; also with the pallial line broken up. Mr. Tyler states that he found it in a burrow in the large Spondylus from Mazatlan; L’pool Col. Aug. 1855. d 26 MAZATLAN BIVALVES Famity PANDORIDZ. Genus LYONSIA, Turton. Syn. Mytilimeria, Conr. Magdala, Leach. 36. Lyonsra picta, Sow. Proc. Zool. Soc. 1834, p. 88.—? B. M. Cat. D’ Orb. Moll. p. 58, no. 506. ?=L,. cuneata, D’Orb.—B. M. Cat. loc. cit. ?= Anatina cuneata, Gray, Spic. Zool. vi. 1828. One perfect specimen of this remarkable shell was found by Master F. Archer, “burrowing” [? nestling] in Spondylus, and now graces his father’s collection. It gapes almost as much as Gastrochena, and displays a large ossicle within. The lunular portion is deeply excavated, and the posterior very greatly produced. Epidermis rugose, occasionally displaying fine radi- ating ridges. The growth is irregular, as usual in nestlers. The amount of gape varies considerably in Mr. Cuming’s specimens. Size of Mr. Archer’s specimen: long. ‘8, lat. 1°2, alt. * 64. The few fragments I found are known at once by the peculiar microscopic structure, described by Dr. W. B. Carpenter in Rep. Br. Assoc. 1847, p. 105. Hab.—Attached to particles of sand in 11 fm., Isl. Muerte, Cuming.—Vancouver’s Island, Col. Cuming—Mazatlan : nestling in Chame, &c., extremely rare: L’pool Col.—? Arica, (Peru,) D’ Orbigny.—The South Temperate analogue appears to be L. Patagonica, ‘‘Northern Patagonia, San Blas,” D Orb.—The W. Indian analogue is L. plicata, Gray. - Tablet 84 contains a perfect young specimen, just beginning its gape, and displaying the radiating strie ; also a fragment of an older one, shewing the hinge.—85, drawings of Mr. Archer’s specimen, made by Master John Jackson. Another species of Lyonsia, allied to A. cuneata, Gray, has been brought from Mazatlan: but as all the fragments even, in the L’pool Col., clearly belonged to L. picta, I have not ventured to include it. Like L. picta, it varies extremely in shape and gape: the latter being generally small, sometimes wanting. Texture smooth, extremely thin, white, glossy. MAZATLAN BIVALVES 27 Famity SOLECURTID. Genus SOLECURTUS, Blainv. 37. SoLEcURTUS AFFINIS, C. B. Ad. O. B. Ad. Pan. Shells, p. 300, no. 510. The author of this species does not point out wherein it dif- fers from its Atlantic analogue, S. Caribeeus. The similarities are evident. The smallest specimen measures long. °3, lat. °84, alt. °14, The largest BX o ST RaENLy a pussies a Ae: HTab.— Panama, very rare, C. B. Ad.—Mazatlan: not common : TP’pool Col. Tablet 86 contains 4 young specimens.—87, 3 adult.—88, 3. lighter colour.—89, 3 with thinner epidermis.* : 38. SOLECURTUS POLITUS, 1%. s. S. t. formd “S. affini” simili, sed subtranslucidd, violaced, extus lined fusca et lineis albicantibus nonniullis radiatd ; epider - mide politissimd, fusco-rubente : intus nymphis elongatis, denticulis 1-2 acutis, sinu pallii versus umbones maxime arcuato ; callositate ab umbonibus, lined fuscd exteriore con- veniente, subexpressi decurrente. Known at once by the brownish violet colour, glossy epider- mis, and dark ray corresponding with a slightly prominent ridge within. In this respect alone it resembles Machera. In the pallial sinus, S. aftinis is intermediate between politus and violascens: in colour, S. violascens is intermediate : in the pro- longation of the nympha, S. politus. This species displays 2 small distinct muscular impressions between the umbo and the anterior adductor, which is oblong, but well defined : in S. vio- lascens, it tapers off irregularly, uniting with these two: in S. affinis it is irregular, not tapering, uniting with the others which are also irregular. The largest specimen measures long. °48, lat. 1°45. alé..” 23. Hab.—Mazatlan: 4 specimens found with affinis: L’pool Col. Tablet 90 contains the most characteristic specimen. * Lower down the coast was found a large specimen which appears a distinct epenee and I therefore append a description, and deposit the shell in the B. M. Cc SoLECURTUS VIOLASCENS. S, t. **S.affini” simili, sed majore, solida, violas- eeunte, rugis epidermidis tenuioribus ; nymphis elongatis, sinu pallii versus um- bones minus arcuato. Long °95, lat. 3° 33, alt. °56.—Hab. 8. W. Mexico, P. P. C. ho QO MAZATLAN BIVALVES 39. PSoLECURTUS , sp. ind. Tablet 91 contains a fragment very flat, white, thin, with irregular very fine strix, shewing within as well as without. Hab.—Mazatlan : in Spondylus washings; L’pool Co’. Famity TELLINID®. Genus SEMELE, Sehum. Syn. Amphidesma, Lam. 40, SEMELE PRoxima, C. B. Ad. Amphidesma proximum, C. B. Ad. Pan. Shells, p. 289, no. 487. Amphidesma proxima, (se.-um) Rve. Conch. Ic. Amph. pl. 3, £120, So much does this species vary in outline, and so closely do some forms approximate to 8. elliptica, that it is still an open question whether C. B. Adams did right in separating it. The colour is typically orange within, and the pallial poytion is punctured. Hab.—Panama, rare, C. B. Adams.—Mazatlan; common ; L’pool Col. Smallest specimen measures long. °04, lat. °05, alt. 02, Largest s ae BOOSH oo sizes Transverse ,, e, Peart atthe teas Tablet 92 contains a pair and a valve, extremely young, which probably belong to this species, though there are lateral teeth slightly developed.—93, 5 specimens, normal state.—94, 5 speci- mens more oblong.—95, 3 specimens very regularly rounded.— 96, 3 specimens, very transverse.—97, 4. young specimens, with very light epidermis.—98, 2 specimens shewing interior.—99, 2 pairs and a valve, deformed in growth. 41. SeMELE Pvenusta, A. Adams. Proc. Zool. Soc. 1853, p. 96. Amphidesma venusta [sc.-um] Fve., Conch. Ic. Amph. sp. 3. ply f. 3: Tablet 100 contains a young valve which agrees in the main with this species. The concentric ridges are not developed, MAZATLAN BIVALVES 29 and here and there a few radiating strie appear under the microscope. Long. °28, lat. °34, alt. °13. Hab.—W. Columbia, Mus. Cum.—Mazatlan, 2 valves; D’pool Col. Genus CUMINGIA, Sow. For amended generic character, ». Proc. Zool. Soc. 1850, p. 24. The shell differs essentially from Semele, in its lateral teeth and ligamental spoon. The animal also differs, as from Syndos- mya, in its irregular cryptophilic habits. ‘The species here enumerated are given under protest. Cumingie are nestlers, like Spheenia and Saxicava, and therefore subject to every possi- ble variation of form. They are fond of growing in company, and squeeze each other up into the queerest shapes. And yet the published specific characters are mainly drawn from the shape alone, with the very variable markings. Almost all the species are variously ribbed concentrically, with minute radiat- ing decussations. The characters of the hinge may be more constant; but alas! neither Sow. nor A. Ad. even allude to them. I have examined about 60 specimens from Mazatlan which might easily be distributed into 20 species, with as good char- acters as those which distinguish Sow.’s species. C. B. Adams distributed his 14 specimens into 6 species, but mercifully for- bore to describe the 4 supposed new ones, on the ground that they are ‘‘probably somewhat variable.” Locality also is no great help: the Atlantic and Pacific, the N. and 8. Temperate species not differing from each other so much as each species may within itself. Mr. Cuming has most kindly come to my rescue, and named the principal specimens according to his types: the smaller ones, in which there is least distortion, 1 have mapped out as well as the microscope would allow me. To do the work satisfactorily would require a very large num- ber of individuals from various localities. The Mazatlan stock was large enough to confuse, not to help. 42. CUMINGIA LAMELLOSA, Sow. Proc. Zool. Soc. 1833, p. 34. Lavignon lamellosa, B. WM. Cat. D’ Orb. Moll, p. 59, no. 518. Lamelle extremely irregular, sometimes scarcely shewing till the creature is nearly adult. Radiating strie not strongly marked. Pallial smus moderate: hinge teeth moderate, pos- terior lateral tooth the longest. (at) U MAZATLAN BIVALVES Smallest specimen measures long. ‘04, lat. ‘06, alt. ‘02. Largest i 53 ey “ADs "72, "24. Tablet 101 contains 3 young valves.—102, the largest (imper- fect) specimen.—103, a C. lamellosa, which had established itself within the empty remains of a Petr. robusta, which had itself gone to dwell inside the skeleton of a deceased relative which had originally constructed the burrow.* The form coarctata was found by Mr. Hanley in Spondylus Lamarckii ; Havre Col. 43, CUMINGIA TRIGONULARIS, Sow. Proc. Zool. Soc. 1833, p. 35.—Rve. Conch. Syst. pl. 49, f. 2.— C. B. Ad. Pan. Sheils, p. 288, no. 480. Lavignon trigonularis, Gray. B. M. Cat. D’ Orb. Moll. p. 59. no. 519. Tolerably well distinguished by the great projection of the ligamental spoon and hinge teeth. The laterals are very short. truncated, and of nearly equal length. Pallial sinus very large. Decussating strie well developed. N.B. The muscular scars often vary in shape with the distortions of the shell. The largest specimen found measures long. ‘Di lat. 62, alt. *32. Hab.—St. Elena : among stones in deep water, Cwming.— Ecuador; St. Elena, D’ Oréigny.—Panama, very rare, C. B. Adams.—Mazatlan : nestling in burrows in Spondylus Lam- arckii; very rare; L’pool & Havre Coll. Tablet 104 contains 1 perfect and 3 broken specimens, of various ages. 4A, CUMINGIA CALIFORNICA, Conr. Journ. Ac. Nat. Se. Phil. 18 =, p. Teeth and pallial sinus intermediate between C. lamellosa and C. trigonularis. Anterior side generally swollen. The largest specimen found measures Jong. °33, lat. °52, alt. °22. Hab.—Upper California, Nuttall—Mazatlan; nestling in bur- rows in Spondylus Lamarckii, very rare ; L’pool Col. Tablet 105 contains 1 young, and 2 adult specimens. * So I have, in limestone from Weymouth Bay, Sphznia Binghami nestling in the tube of a Gastrochena modiolina which had been formed by soldering together portions of a Thracia distorta through which it had burrowed. MAZATLAN BIVALVES 31 45, CUMINGIA: , sp. tnd. Messrs. Cuming and Hanley who possess perfect specimens of this shell, regard it as a new speeies. Let those describe it however who understand the specific marks in this genus. The few valves found were all toothless. The pit and tooth marks are extremely small; shell small, delicate, flat, triangular. It closely resembles C. striata, A. Ad. Proc. Zool. Soc. 1850, p. 25, and has affinities with Syndosmya tenuis. Long. °3, lat. °38, ait, “15. Hab.—California, Mus. Cuming.—In Chame, extremely rare : Mazatlan; L’pool & Havre Coll. Tablet 106 contains 2 valves. Tablet 107 contains 1 of three small specimens which I can- not identify with existing species. The form is very regular, like C. Cleryi, A. Ad. but the shell is convex, and marked as in the typical species. The teeth bear most resemblance to C. Californica, Conr. Long. (18, lat. °23, alt. °11. Hab.—Mazatlan: in Spondylus Lamarcki, nestling im bur- rows: extremely rare; L’pool Col. Genus SANGUINOLARIA, Lam. 46. SANGUINOLARIA PURPUREA, Desh. Proc. Zool. Soc. 1854, p. 346, no. 137. Compare Sanguinolaria tellinoides, A. Adams in Proc. Zool. Soc, 1849, p. 170: pl. 6, f. 6. ?=Tellina (non Strigilla) miniata, Gould’s Plates, ms. This shell is extremely likeS.tellinoides, but differs in texture. “one being thin and delicate, the other coarse and strong in comparison,’ Cuming. Gould’s description may prove his shell to be different. It seems almost as much a Tellina as T.rufescens. ~ It is the Pacific analogue of S. rosea. Only 2 specimens were found in the L’pool Col. (Mus. Archer & B. M.); but as several specimens were in the London shops, it is probable that more were sent in the Havre Col. Zong. 1°07, lat. 1°73, alt. 47. Hab.—Mazatlan: extremely rare ; Z’pool Col. Tablet 108 contains 1 specimen. 32 MAZATLAN BIVALVES Genus TELLINA, Lin. 47. TELLINA RUFESCENS, Chemn. Chemn. vi. p. 105. t. 11. f. 97.—Schroeter, Hinl.t. 3, p.5. no. i1.— Dilw. Desc. Cat. vol. i. p. 85.—Knorr, vol. vi. t. 12, f. 1.— Hand. in Sow. Thes. Conch. vol. i. p. 807, pl. 63, f. 213. =T. operculata, Gimel. p. 3235, no. 32, Var. exc.—Lam. ed. Desh. 1836, vol. 6, p. 192.— Wood's Ind. Test. p. 19, no. 37.— Hanl.« Descr. Cat. p, 62, t. 4, £. 37. =T. cruenta, Solander, ms.—Portland Cat. p. 58, lot 1360. =T. opercularis Sow. Gen. no. 31, f. 1—Desh. Ene. Meth. vers t. 3, p. 1010, no. 9. This shell must not be confounded with T. rufescens of Gmel. which= Venus decussata, var ; nor with the too-similarly named T. rubescens of Hanl., a shell found as far north as 8S. W. Mexico, (P. P. C.) but not yet obtained from Mazatlan. T. rufescens is known at once by its large size, red colour (often banded with whitish,) and greatly produced beak. Lower valve pro- jecting, as in Corbula, and displaying faint radiating lines, which are generally obsolete on the upper. It gapes at both ends, and nearly approaches Sanguinolaria. Zong. 1°73, dat. Salt: 11. Hab.—Coasts of Brazil, Humphreys.—Caribbean Sea, Lam. “Cab. de M. Dufrene.”—(Indian Ocean, Wood.)—Tumbez, (Peru,) in soft, sandy mud, 5 fm., Cuming. Mazatlan; rare; L’pool & Havre Coll. The authorities for the Atlantic Ocean do not appear satis- factory. On the other hand, the shell being known to the old writers is in favour of its having been brought from the West Indian seas. Tablet 109 contains 1 small specimen from the L’pool Col., and 1 large one from the Havre Col. in which it was less un- common. 48. Tectina Broperipit, Desh. ns. (teste Cum.) Compare Tellinides purpureus, Brod. & Sow. Zool. Journ. vol. iv. p. 363.—Zool. Beech. Voy. p. 153, pl. 42. f. 2—=Tel- lina purpurascens, Hanl. Descr. Cat. p.74, swppl. pl.9, f. 18: do. in Sow. Thes. Conch. p. 295, no. 141, pl. 62, f. 194. MAZATLAN BIVALVES >; Shell closely resembling T. purpurea; from Real Llejos, Cuming. It differs from the plate in Beech. Voy. in having the umbos less pointed and the teeth smaller. The surface 1s crowded with extremely close concentric strie, decussated (except on the fold area) by very fine radiating lines, which beeome obsolete, in one valve only, on the ventral portion. The fold area is nearly smooth (except lines of growth) on one valve ; on the other, with rather sharp raised ridges, carrying on generally every other one of the concentric strie. EHpiden mis light brown, very thin, coarser on the fold area. The species mucb resembles (though smaller) T. princeps, a valve of which was sent from 8. W. Mexico, (P. PC.) It gapes on each side, and might almost pass for a Sanguinolaria, but for its flatness. Long. 1°18, lat. 2°12, alf. °31. Hab.—Mazatlan, 3 specimens (Mus. Archer, Darbishire, B. M.) L’pool Col. Tablet 110 contains one specimen. AQ. Tertina PP MazarLantica, Desh. YT. Mazatlandica, Proce. Zool. Soc. 1854, p. 359. Tablet 111 contains a minute fragment which may be the young of this species, though the characters of the hinge are somewhat different. The Cumingian type measures long. ‘79, lat. Ii3s all. 32: Hab,—Mazatlan : Col. Cuming.—?? Do. in Spondylus washings, Ly pool Col. 50. Tenutina Dompet, Hanl. Proc. Zool. Soc. 184A, p. 144.—Hanl. in Sow. Thes. Conch. p. 323.—C. B. Ad. Pan. Shells, p. 282, no. 464. A plain, white, oblong shell, much swollen and produced anteriorly. Zong. 1°1, lat. 1°45, alt. °5. Hab—Panama, in sandy mud, 12 fm. Cwmzng.— Panama, rare. C. B. Ad.—Mazatlan, 2 specimens, L’ pool Col. Tablet 112 contains one specimen. \ 34. MAZATLAN BIVALVES 51. TeLLIna FELIx, Hani, Proc. Zool. Soc. 184A, p. 71.—Hanl. in Sow. Thes. Conch. vol. 1. p 281: pl. 58, f.52.—C. B. Ad. Pan. Shells, p. 282. Closely resembling a West Indian species in form and colour : Hani. compares it with T. donacina. Long. ‘43, lat.*7, alt. °2. Hab.—Sandy mud, 6—10 fm. Panama, Cuming.—Panama, rare, C. B. Adams.—Mazatlan : extremely rare, L’pool Col. Tablet 113 contains 1 perfect valve. 52. TELLINA STRAMINEA, Desh. Proc. Zool. Soc. 1854, p. 363. One specimen was found, about two-thirds the size of the Cumingian type whith measures long. ‘33, lat. .48, alt. °17. It is known from neighbouring species by the rounded very faint concentric strie, which are clearly displayed by the microscope near the umbo of the adult shell. Hab.— Gulf of California, Col. Cuming.—Mazatlan, from Spon- dylus washing: L’pool Col. Tablet 114 contain the specimen.—l15 contains a minute valve and fragment which probably belong to the same. 53. TELLINA DONACILLA, 2. Ss. T. t. gun. donaciformi, valde transversd, tenui, compressa, alba, concentrice liratd ; liris acutis, subequidistantibus, alternis, medio sepe evanescentibus, antice rarioribus ; epidermide tenuwis- sima, hue et illue liras radiatim decussante ; postice valde producta, subrotundata ; antice angulata, truncatd, brevissima : marginibus ventralt dorsalique fere parallelis ; cardine dentibus duobus quarum unus bifidus cardinalibus, laterali uno postico brevi appropinquante, extante. Related apparently to T. donaciformis, Desh. from Torres Straits ; from which it is known at once by the strong projec- ting lateral tooth. The shape is so remarkably like a Donax, that I have only varied the termination from the British T. dona- cina. The specimen is young, but well characterized except in the inner surface, which does not display the muscular impres- sions. Wong. ‘08, lat. °14, alt. °05. Hab.—Mazatlan: off Spondylus Lamarckii, Z’pool Col. Tablet 116 contains the only valve found. MAZATLAN BIVALVES 35 54. TELLINA PUNICEA, Born. Test. Mus. Ces. Vind. p. 33, pl. 2, f. 2.— Dorset Cat. p. 30, pl. 7, f.5.—Linn. Trans. vol. 8, p.50.— Brit. Mar. Conch. p. 66.— Brown Illustr. Conch. Gr. Br. p. 100.—Gmel. Syst. Nat. p. 3239.— Wood, Ind. Conch. p. 20, no. 47.—Dillw. Deser. Cat. p. 90.—Lam. ed. Desh. vol. 6, p. 196.—Schroeter Fini. t. 3. p. 22, no. 79.—Desh. Enc. Meth. vers. t.3, p. 1011. no. 12.— Hanl. in Sow. Thes. Conch. vol. 1. p. 239, pl. 58, f. 89, and pl. 60, f. 154—B. M. Cat. Moll. D’ Orb. p. 61, no. 433.— Forbes § Hanl. Br. Moil. vol. 1, p. 314. =Donax Martinicensis, Lam. teste Gray. =Tellina alternata, Sow. teste Gray. = , angulosa, Gime/. teste Desh. = ,, simulans, C. B. Ad. Pan. Shells, p. 284. ?=striata, Chemn. Conch. t. 10, tab. 170, f. 1654-5 ; teste Dillwyn § Desh. : non Forbes & Hanley, Br. Moil., nec Hanl. i Thes. ° The late respected and very accurate Prof. Adams made his T. simulans out of a valve he found of this species on what was (to him) the wrong coast. Unfortunately for his theory, the very slight differences he relied on (deeper furrows continued over the flexure, interspaces less flattened, and lateral teeth nearly obsolete) are not constant in the Pacific waters: and if one shell is common to the two oceans, which he is obliged to allow in the case of Crepidula unguiformis, why may not this be? The shell is known at once by its regular Tellinides shape, solid texture, pink colour variously banded with white, and deeply channelled furrows, some of which generally coalesce on one side before they reach the flexure. The angle of the ligamental area is more or less developed: the passage of the sulcations over the fold varies not only in different specimens, but in the same shell, in the opposite valves, or from young to old. The closeness and flattening of the ribs, the colour and the size of the lateral teeth also vary considerably, though I have only had an opportunity of examining about 40 specimens. Long.1'15, lat.1°9, alt. °47. Hab.—([Coasts of Britain, Pulteney, Wood, &&¢|—‘‘A West Indian Shell, introduced into our Fauna through having been figured in the Dorset Catalogue as identical with striata Chemn.” Forbes & Hanley— Mediterranean, Lam. ed Desh.— Cuba, Sagra in B. M. Cat. p. 36.—Brazils, D’ Orb. in B. M. Cat. p. 61—St. Domingo, Sir. R. Schomberg, in B. M.— Trinidad, Hanl.—This, like many other West Indian shells, 36 MAZATLAN BIVALVES has found its way into British and Mediterranaen lists with- out sufficient authority. . T. striata, Chemn. (=angulosa, Gmel.,=leta Palt.= Don. Mar- tinicensis, Lam.=T. punicea, Turton, Dillw. &c.) hab. W. Indies Coasts of Guinea, and Rhode Island, U. S.; Chemn. T. simulans, C. B. Ad. had. Xipixapi in W. Columbia, sandy mud, 10fm.; Cwming.—Panama (1 valve), C. B. Ad—Mazat- lan: very rare; L’pool Col; rare, Havre Col—Guayaquil, Hinds. Tablet 117 contains 2 pairs and 1 valve, shewing variations. 55. TeELLiIna ?Cuminei, Hanl. Proc. Zool. Soc. 1844, p. 59.—Sow. Thes. Conch. vol. i. p. 223, pl. 58, f. 72.—C. B. Ad. Pan. Shells, p. 281, no. 463. Tablet 118 contains 2 fragments which seem to present the colours and markings of this species. ffab.—Guacomayo, in coral sand, Cuming. Panama, extremely rare, C. B. Adams.— Mazatlan : fragments in shell washings, extremely rare; L’pool Col. 56. TELLINA PEBURNEA, Hani. Proc. Zool. Soc. 1844, p. 61—Han!.in Sow. Thes. Conch. vol. 1. peed ipl. os... Tablet 119 contains a fragment with deep sulci and stout ribs, which may belong to this species. Hab.—Tumbez, (Peru,) in soft sandy mud, 5fm., Cuming.— ? Mazatlan: in Spondylus washings, L’pool Col. 57. P TELLINA REGULARIS, 7. s. ?T. ¢. jun. suborbiculari, convexiusculd ; margine ventrali sub- recto, umbonibus prominentibus ; diaphand, alha ; tenuissime et confertim concentrice liratd ; liris acutis, interstitsis aut levihus aut huc et illuc lineis radiantibus vix decussatis ; flerurd nulla : ligamento miminw ; cardine dentibus cardinalibus 3, paululum divergentibus, lateralibus 2 distantibus, validis. An aberrant species, so regular in form that externally it would range better with Kellia. It wants the spoon-shaped -_ MAZATLAN BIVALVES 37 rocess of Cumingia, but the ligament is scarcely apparent. Long. °06, lat.°07, alt. OA. Hab.—Mazatlan: from Spondylus washings ; Z’poo/ Col. Tablet 120 contains all that was found; viz. 1 perfect valve with a portion of the other. 58. TELLINA LAMELLATA, 2. S. T.t. “ Telline lire” simili, sed magis equilaterali, et carind umbonum carente : lamellis acutissinis, irregulariter distanti- bus ; umbonibus valde prominentibus. A_ beautiful little shell, very flat, thin, white, transparent ; cardinal and lateral teeth moderately strong; spaces between the lamelle smooth ; outline oval, very regular except where the umbos project ; flexure wanting: It might have been the young of T. lira, but for the entire absence of the stout umbonal ridge of that species. Long. °1, lat. °13, alt. *03. Hab.—Mazatlan ; nestling on back of Chama and Spondylus Lamarckii, extremely rare; ZL’ pool Col. Tablet 121 contains 1 pair and 2 opposite valves. 59: TeLiina ?P puELLA, C. B. Ad. C. B. Ad. Pan Sheils, p. 283, no. 468. Tablet 122 contains an open pair and a valve which may belong to this species. I think however that the valve is dis- tinct, and displays certain symptoms of Semele, of which I have not seen the very young shell, and am therefere ignorant of its variation in growth. An unfortunate cough made away with the opposite valve, which however had previously adhered by an external ligament. Whether there be an internal liga- ment as well, repeated microscopic examination has as yet failed to determine. Long. °075, lat. °095, alt. '035. 60. TrLiina ?? peLIcaTtuLa, Desh. _ Proc. Zool. Soc. 1854, p. 363. Tablet 123 contains a fragment which may possibly be the young of this exquisitely beautiful species. Mr. Cuming’s unique specimen displays, in addition to the features recorded in Desh.’s description, a pretty general penciling of a dark Sept. 1855. € 38 MAZATLAN BIVALVES colour in irregular radiating lines, crossing the oblique strie. It measures long. °37, lat. °64, alt. °12. Hab—Mazatlan ; Col. Cuming.—?? Mazatlan; in Spondylus washings ; L’pool Col. 61. TELLINA BREVIROSTRIS, Desh. Proe. Zool. Soc. 1854, p. 362. This little valve seems to suit the description above quoted: it differs from T. gracillima in being very inequilateral, the lateral and cardinal teeth very strong, and the lamelle very regular, not much raised and rather close. Long. ‘03, lat. 05, alt. ‘O15. Hab.—Central America and California [?Gulf], Col. Cum- ing.—Mazatlan ; extremely rare, jun; L’pool Col. Tablet 124 contains 1 valve, and a fragment of a larger specimen. Nothing else was found. 62. TELLINA P DENTICULATA, Desh. Proc. Zool. Soc. 1854, p. 365. Shell like a little T. crassa, with exceedingly large and projecting lateral teeth ; muscular impressions strongly mark- ed. Pallial line indistinct. The outside of both valves is worn, and prevents the identification of the species. Lony. ‘065, dat:-O7; alt. -O2. : iTab.—Unknown, Col. Cuming.—? Mazatlan ; from Spondylus washings ; L’pool Col. Tablet 125 contains the only specimen. 63. TELLINA ————, sp. indet. Tablet 126 contains an imperfect valve remarkable for its 3 strong rather divergent cardinal teeth; the lateral ones are not developed, but there appear spaces for their reception from the opposite valve. Hab.—Mazatlan ; off Spondylus ; L’pool Col. 4 64. TELLIna —————., sp. indet. Tablet 127 contains a broken valve remarkable for its sub- diaphanous concentric lines on a smooth surface. A fragment MAZATLAN BIVALVES 39 with the surface indented may be an older form of the same species. Shell suborbicular, lateral teeth distinct. Hab—Mazatlan ; from Spondylus washings ; L’pool Col. 65. Tentina Burnett, Brod. & Sow. Zool. Journ. vol. iv, p. 362, t. 9, f. 2—Hanl. Descr. Cat. p. 72, t. 13, f. 51.— Hanl. in Sow. Thes Conch. vol. i. p. 271. =Lucina cristata, Recluz, teste Jaz. After examining more than 800 specimens of this most aberrant shell, I cannot quote any noteworthy variations. It seems as though the creature was quite satisfied with its beauty, without endeavouring to improve it. The valves however are occasionally a little more bent, and the strie and knobs a little more or less close. To the shape of a Myadora, it adds the hinge of a Tellina. It has an Atlantic analogue, T. lunulata, found fossil in the Pleistocene beds of 8S. Carolina. In this however, the left and not the right valve is flat. A species of similar form is found fossil in the paleozoic rocks, agreeing more with the Atlantic shell. (Woodw.) T. Burneti owes its present wide distribution in collections to this importation from Mazatlan: even this spring a specimen was sold ata London sale for 15s. Long. 1°23, lat. 1°37, alt. °23. Hab.—¥ound in the Estuary of Mazatlan, among the shoals of large Pinne which are left dry at low water, Lieut. Bel- cher.—Salango, W.Columbia, Hanley.—St. Elena, Cuming.— Gulf of California, Mus. Cum.—W. Columbia, Lieut. Freer in Bristol Museum.— Mazatlan ; not uncommon ; L’pool Col. Tablet 128 contains 3 specimens of different ages. Genus STRIGILLA, Twrt. Strigilla Turton, pars, Tellina, auct. A group of Tellinids conveniently separated for their Lucina-like shape and di- varicated sculpture, 66. SrrictLua (Tellina) carnarta, Linn. Tellina carnaria, Linn. Syst. Nat. ed. 12, p.1119.—Donor. Br. Shells, vol. u. pl. 47.—Linn. Trans. vol. viii. p. 57.— Dorset Cat. p. 31, pl.5, f. 6.—Turt. Conch. Dict. p. 177.—Chemn. Conch. Cab, vol. vi. p. 130, pl, 13, f. 126.— Wood Ind. Test. 4G MAZATLAN BIVALVES p. 22, no. 79.— Dillw. Descr. Cat. vol. i. p. 100.—Ginel. p. 3240, no. 70.—Schroet. Hinl. t. 2, p.660.—Mont. Test. Br. p.73.— Born. Mus. p.37, t.2, f.14.—Desh. in Lam. An. s. Vert. vi. 209.—Hanl. Rec. Sh. vol. i. p. 72, pl. 4, f. 79.—Hanl. in Sow. Thes. Conch. vol. i. p. 260, pl. 56, f. 37, 38.—Forbes & Hanl. Br. Mol. vol. i. p. 313.—Middendorf Mal. Ross. Abth. iii. p. 60, no. 3—B. M. Cat. D’Orb. Moll. p. 61, no. 536.— B. M. Cat. Sagra Moll. p. 36, no. 434. Cardium carneosum, Da Costa, Brit. Conch. p. 181.—List. Conch. t. 339, f. 176. Lucina carnaria, Lam. An. s. vert. t. vi. p. 227, no. 8.—Flem. Br. An. p. 442.— Brit. Mar. Conch. p. 75.— Payr. Cat. de la Corse, ». 41, no. 68. Strigilla carnaria, Turt. Dith. Br. p. 118, pl. 7, f. 165. 2=Strigilla miniata, Gould’s plates. T have not been able to see Gould’s description; but as Mr. Nuttall informs me that this shell is plentiful at Sta. Barbara and as his specimens are even more like the W. Indian ones than the Mazatlan shells are, I presume that the 8. miniata is a further development of the theory which produced T. simulans, C. B. Ad. Vt appears to be a very widely diffused species, being one of the very few found N. and 8, of the Gulf of Cali- fornia, and spreading through the Atlantic ocean probably to the Mediterranean and Euxine. Valves have been thrown up on our own shores.—The Mazatlan specimens are generally much paler than the W. Indian, but some have as deep a tinge. The character of the markings is exactly alike, though they vary among themselves in the crowding of the strie, &c. They ‘are occasionally marked with a yellowish tinge, and are gen- erally more or less stained with black, probably from the mud in which they lived. The shell appears to differ from T. sin- cera, Hanl., found by C. B. Ad. at Panama, (rare.) Hanl. gives it as from N. W. Coast of America on the authority of Dr. Sin- clair; but Nuttall’s Californian specimens are undoubtedly T. carnaria. Long. °9, lat. °98, alt. °42. Habh.—{ Scarborough, Devon and Cornwall, Da Costa, &e. |— American Ocean, Wood.—Jamaica and Barbadoes, Lister.— Curacoa, Gronovius.— W. Indies, W. Columbia, Hanl.— Cuba, Sagra.—Brazils, D’ Orb.—Mediterranean, Lam. Risso; non Philippi, nee Forbes; dubitat Middendorf.—Corsica, Payrandeau.—Naples, P. P. C.—Sudate, Black Sea, teste MAZATLAN BIVALVES Su Rathke, Siemaschké.—Santa Barbara, abundant, Nuttall.— Mazatlan: not common; L’pool Col. Tablet 129 contains 6 pairs and 2 valves, shewing variations. The smaller valve may be T. cicercula, Phil., in Zeitschr. fiir Mal. Feb. 1846, p.19. I cannot however separate it from S. earnaria, of which it appears the young. The description of T. cicercula exactly applies to this, which is the left valve. Menke in quoting the species among Melchers’ Mazatlan Shells, Zettschr. f. Mal. 1847, p. 188, no. 53, says that it is only the left valve which possesses the sculpture in question : so does the left valve of T. carnaria, and that alone. Menke Joc. ett. deseribes a new species, T. areolata, from the West Indies, intermediate between T. cicercula and T. carnaria, with a similar smooth space on the left valve.—Philippi also describes from Mazatlan (loe. cit.) T. lenticula, T. dichotoma, and T. ervilia. In his Abbil. Conch. for Aug. 1846, p. 24, he also gives the ancient T. pisiformis, Linn. (along with Diplodonta semiaspera) as common to Mazatlan and the Caribbean Sea. Mazatlan must be rich in Strigille, according to Philippi! 67. PSTRIGILLA LENTICULA, Phil. Tellina lenticula, Phil. in Zeitsch. f. Mal. 1846, p. 19. Tablet 130 contains a broken specimen which probably be- longs to this species, which, says Philippi, while agreeing in form and size with T. pisiformis, has the sculpture of Lucina digitaria. It may however belong to Lucina eburnea, Rve. Conch. Icon. pl. 8, f. 49, found in sandy niud, 11 fm., St. Elena and Panama, Cuming. Hab—Mazatlan, Philippi? Do. fragments, off the back of Chama; L’pool Col. 68. Tablet 131 contains a fragment of a thin shell of moderate size, perhaps a Psammobia, (possibly an unknown Donax,) strongly angulated, with very fine, slightly rugose stric. coarser on the angular part. It is white, slightly bordered with orange. Hab.—Mazatlan ; confined in the mouth of Trivia sanguinea ; LT’ pool Col. = aS. 42 MAZATLAN BIVALVES Famity DONACID. Genus IPHIGENIA, Schum. Syn. Capsa, Lam. 1818, (non 1801.) Donacina, Fer. 69. IpHIGENIA ALTIOR, Sow. Capsa altior, Proc. Zool. Soc. 1832, p. 196, (teste C. B. Ad.)-—- Mill. Syn. Test. Viv. p. 225.—Hanl. Descr. Cat. p. 86.— Hanl. in Suppl. to Wood’s Ind. Test. pl. 14, f. 34.—C. B. Ad. Pan. Shells., p. 276, no. 453. Shell very variable iu outline, sometimes nearly equilateral, sometimes much produced anteriorly, sometimes incurved at the posterior ventral margin. The outside has the usual olivaceous epidermis. The inside is more or less stained with violet. Bifidity of cardinal teeth more or less developed : lateral teeth almost evanescent in one valve, absent in the other. Smallest specimen measures long.1°, lat. 1°37, alt. °56. Longest a in re ony Caos. - i oie Aberrant _,, “s CPR A Deere be 05 fF Hab.—Gulf of Nicoyia, in coarse gravel, 12 fm. Cuming.— Var. Tumbez, thin mud, 5 fm. Cuming.—St. Elena, Jay.—Panama, extremely rare, C. B. Adams.—Mazatlan: very common ; ‘pool & Havre Coll—The Atlantic analogue is I. Brazili- ensis. A closely allied species is from the Gambia; Chief Justice Rankin, Bristol Mus. Tablet 132 contains 5 specimens in the normal state.—133, 5 specimens more transverse.—134, 5 specimens indented.— 135, 2 specimens of abnormal growth.—1386, 1 specimen with very thin epidermis. 70, IPHIGENIA PLEVIGATA, P cus. This shell is regarded by Dr. Gray as an abnormal variety of I. altior. It has much more the shape of I. Braziliensis. The most deeply indented I. altior is far removed from it. Mr. Cuming has similiar specimens from the same coast, which he regards as an undescribed species. I have seen it with the name Capsa levigata, but do not know on what authority. It is characterized by very overlapping umbos; subcarinated, subtruncated posterior side; deep posterior ventral sinus ; MAZATLAN BIVALVES 43 anterior side much elongated. Long. 1°52, (ad sinum 1°37,) lat. 2°28, alt. ‘9, (ad sinum °78.) Hab:—Mazatlan ; extremely rare; L’pool Col. Tablet 137 contains the only specimen I found: Mr. White- head of Liverpool found another. : Genus DONAX, Linn.* 71. Donax carinatus, Hanl. Proc. Zool. Soc., 1843, p.5.—Rve. Conch. Icon. pl. 2, sp. 11.— Wood's Suppl. pl. 14, f. 28. Shell with a blunt keel, and posterior area covered with slightly expressed strize which are scarcely rugose here and there. Epidermis very thin, deciduous except round the mar- gin. Ventral margin almost always regularly excurved. The purple colour generally predominates in this, as the chesnut in D. culminatus. Form and markings very constant, except, as usual, in the proportion of length and breadth. Long. °93, lat. 1°62, alt. °63. Hab.—San Blas, Gulf of California, Reeve.-—Tumaco, Hinds, B. M.—Mazatlan ; rare; L’pool Col. Tablet 138 contains 2 specimens in the normal state, and one with two remarkable lamine in the interior of one valve, near the posterior adductor. 72. DoNAX CULMINATUS, ?1..s. D. carinatus, var: Hanl. ms. teste Cuming. D.t.“ D. carinato” simili, sed cariné multo acutiore, producta, margine ventrali sepe prope carinam paulum incurvato ; niten- tiore ; striis radiantibus obsoletis et crenulatione interna convent- ente crebrioribus ; ared posticd striis radiantibus creberrimis valdeextantibus, granosis, granis versus marginem rugosis ; castaneo-purpureo. Thad passed this shell over as the young of D. carinatus, till I obtained a number of large valves with other West Coast shells, which at once displayed the remarkable characters of the posterior area, the sharp ridge, and the very granular crowded strie. Having examined more than 60.specimens of D. carin- * The specific termination being given as feminine in P. Z. S., B. M. Cat. D’ Orb. Moll., Rve. Conch. Icon., Jay’s Cat. &c., it is desirable to remember that Donax is masculine both in Latin and Greek: (v, Lex.) In quoting, the termin- ations are altered accordingly. 4A MAZATLAN BIVALVES atus, without seeing the slightest approach to these characters, I am obliged for the present to consider them specific. Size of the Mazatlan specimen ; Jong. °55, lat. °95, alt. °33. Ordin- ary size, as in D. carinatus. Hab.—Mazatlan ; 1 young specimen ; L’pool Col.* Tablet 139 contains this specimen, and two valves, probably from the Central American coast. 73. DoNAX TRANSVERSUS, Sow. Tank. Cat. App. p. 4, no. 226.—Rve. Conch. Icon. pl. 6, sp. 36. Known from D. scalpellum, Gray, (Gulf of California) by the peculiar incurving of the anterior dorsal line; and by the character of the posterior area, which has at the margin one large and two small flexures, while the surface is covered with radiating strice, very finely and granularly serrated. Long. °56, Piel 34. alt. 53. Hab.—Mazatlan; extremely rare; teste R. Tyler, Hsq., who found a fresh valve concealed ina Chama from the L’pool Col. The other valve is nowhere to be found. Tablet 140 contains this valve, most kindly presented by Mr. Tyler. 74. Donax asstmitis, Hanl. Proc. Zool. Soc. 1845, p.17.—C. B. Ad. Pan. Shells, p, 277. no. 454.— Rve. Conch. Icon. pl. 2, sp. 10. This species is used for food at Panama, where the natives scoop to its depth, and keeping to the same level find them in great abundance. (C. B. Ad.) Long. °92, lat. 1°36, alt. °51. Hab.—Panama, Mus. Cuming.—Do. very plentiful, a few inches deep in sand at 3-4ths tide level, C. B. Adams.—Mazatlan, Lieut. Green.—Mazatlan ; 1 valve only ; L’pool Col. Tablet 141 contains the solitary valve. 75. Donax PUNCTATO-STRIATUS, Hanl. Proc. Zool. Soc., 1843, p. 5.—Rve. Conch. Icon. pl. 3, f. 16. Var.=D. radiatus Val. in Humb. Rec. vol. 11, 1833. ?=D. flexuosus, Gould's plates. * An extremely similar shell is given in the Bristol Museum as Donax rugosus, Dy, Cutting, W. Indies. MAZATLAN BIVALVES 45 Although there is little doubt that Valenciennes’ species is the rayed variety of this shell, and therefore has priority, yet as his description is not accurate enough for certainty, and as it only applies to a very small part of the species, Hanley’s expressive name is retained. The punctatostriate character however is by no means peculiar to this shell. Some forms are exceedingly hard to tell from D. Conradi, Desh. ; including D. contusa, Rve. The following are believed to be the main characters of the shell. Surface smooth, shining, with very thin deciduous epidermis, rarely seen. Not grooved, but with rows of extremely fine dots indented as with a bookbinder’s tool. Rows often intercalated near the anterior end. Mar- gin with strong squarish crenations inside: the same outside toward the posterior slope; about the middle, grooves appear dividing each, answering to the intercalary rows: at the end a broad surface is channeled off, in which each crenation gives off a fang something like a (*) to join the external rays. This intricate and very characteristic structure will generally tell the species at once from the aberrant forms of D. Conradi. In the posterior ‘slope, the punctate rows are very close; in the lunular portion entirely absent. The ordinary colour is pale yellow or white, sometimes arich orange yellow; generally rayed with purple about the lunule with occasional stains elsewhere ; often tinged with green about the posterior slope and umbos, occasionally rayed with brown (=D. radiata, Val.) with the rays often not corresponding on the two valves. Umbos white or pale yellow, sometimes rich transparent orange, sometimes with a penciling of purple, sometimes two purple spots. Shape normally trapezoid, with the umbos sub-central : but often with the posterior part shortened, and the anterior much elongated. The end is then tapering: but often it is short and very gibbous. Ventral margin almost always well developing the angular swelling. Inside generally rich purple. Lateral teeth short but very strong, the anterior truncated : in the opposite valve small. Largest specimen measures Jong. 1°15, lat. 1°64, alt. °6. Transverse ,, as i NS ae he, MOS W estas Slee Stumpy 29 ” oe) ; 79, ” i 06, sos 48. Smallest s * i MEG? Sosa lds. cai woe Hah—South America, Capt. Ld. Byron |? |.—Mazatlan ; in extreme profusion ; L’pool Col. Tablet 142 contains 15 specimens, normal shape, rich orange yellow.—143, 10 sp. same colour, transverse shape.—144, 9 sp. 46 MAZATLAN BIVALVES same colour, lunular purple ray on one valve only.—145, 9 sp. same colour, purple rays absent.—146, 10 sp. and 2 valves, pale yellow: this is the most frequent state.—147, 8 sp. white, normal shape.—148, 8 sp. white, transverse.— 149, 12 sp. white and pale yellow, with irregular pale violet concen- tric bands.—150, 5 sp. orange yellow, similarly banded.— 151, 5 sp. stained with purple and green.—152, 15 sp. yellow. green at umbos and posterior slope.—153, 15 sp. whitish, band- ed with violet, green at posterior slope.—154, 9 sp. plain yellow with greenish slope.—155, 9 sp. white with greenish slope.— 156, 7 sp. orange yellow stained with purple.—157, 2 sp. and l valve, do, highly coloured, form approaching D. Conradi.— 158, 6 sp. with broad brown rays.—159, 6 sp. with very faint rays.—160, 5 sp. shewing distorted growth. Besides these were found a few scores of specimens which, when examining D. punctatostriatus I have generally turned over to D. Conradi; when examining the latter, have been dis- posed to turn back again. They are here grouped according to the preponderance of characters.—Tablet 161 contains D. punc- tatostriatus approaching D. Conradi, 4 sp. whitish.—162, 6 sp. yellow.—163, 3 sp. rayed.—164, 2 sp. yellow, transverse.—165, 3sp. reddish, transverse.—166, 3 sp. whitish, narrow margin. 167; 3. sp. very gibbous.—In all 192 shells, the result of very frequent elimination from an examination of many thousand specimens ; no two probably being exactly alike. 75 (6.) Donax P PUNCTATOSTRIATUS, var. CHELATUS. D. ?punctatostriatus, t. maxime inequilaterali, margine ven- trali vix angulato: superficie posticd dense liratad, liris ex- pressis radiantibus : interstitiis dense decussatis, lineolis valde impressis : sculpturd partem versus anteriorem, im lineas punc- tarum mutante, punctis angulatis : margine plerumque simplici, epidermide densa rugosa tecto. Nearly 40 specimens have occurred, agreeing in the above characters, while only 2 shewed the least disposition to depart towards the ordinary type. Shape extremely inequilateral, anterior end much prolonged. Sculpture deeply marked on the posterior and posterior ventral part ; with elevated ridges, and the furrows not simple rows of dots as in D- punctato-stria- tus," but with short lines impressed as with a file-cutter’s tool. These gradually subside anteriorly into punctate striation, but even then the dots are angulated, not round. ‘There is a large “ MAZATLAN BIVALVES 47 smooth lunular portion, not specially coloured. The margin is generally simple, nearly asin D. Conradi: and when it has the interealary grooves proper to D. punctatostriatus, they are rarely carried up into intercalary rows of dots. The epider- mis is remarkably thick round the margin. Colour sometimes white, occasionally yellow, but generally stained with rich reddish purple. Whether it be an aberrant variety of D. punc- tatostriatus, or a distinct species, must be determined when more specimens have been examined, or the animals studied. The largest but not characteristic specimen measured Jong. ‘91, bee VST; alt. 57: Hab.—Mazatlan ; very rare; L’pool Col. Tablet 168 contains 3 specimens, white, yellow and purple. 76. Donax Conranti, Desh. Proce. Zool. Soc. 1854, p. 351.—Rve. Conch. Icon. pl. 5, sp. 29. +D. contusus, Rve. Conch. Icon. pl. 4, sp. 24. +D. Californicus, Conr. teste Desh. ms. B. M. & Col. Cuming : nequaquam, teste Nuttall. + D. culter, Hanl. Proc. Zool. Soc. 1845, p. 14.—Rve. Conch. Icon. pl. 4. sp. 21. It is not without the most careful, laborious and often repeated examination of upwards of 1,000 specimens that I have felt compelled to depart from the views of the illustrious Deshayes and the very accurate Hanley, and group together. the species above quoted. The D. Californicus, teste Nuttall whose shells were the basis of Conrad’s descriptions, is very different from the shells so named by Desh. in the Br. Mus. and Col. Cuming; the former being a smooth, gibbous, sub- triangular shell, more like a young D. punctatostriatus, though quite distinct. The name Conradi is preferred to culter which has priority, as expressing the adult form, and as leaving contusus and culter for the use of those who believe in the species, without introducing confusion. The shells wrongly called D. Californicus are simply the white variety of the forms contusus and culter. This creature loves liberty both in form and colour. The shape is generally transverse, not unlike the large variety of D. anatinus, slightly swollen ventrally, with a flattening towards. the posterior end. Sometimes it tapers off at the anterior part, which is then somewhat flattened: sometimes the whole shell ’ 48 MAZATLAN BIVALVES is very gibbous: sometimes subtriangular, and even taking the form of D. punctatostriatus. The lines of growth shew that the adult by no means thinks it necessary to preserve the form of early life: it being very common to observe the posterior part much developed in the young, while it is narrowed off in matu- rity ; or the shell is sometimes sub-oval when young, and very transverse afterwards. In colour there are similiar variations ; the young shell abounding more in purple, while the adults reserve that colour for the inside, and content themselves with a greenish gray. Orashell of an ochre yellow when young will change afterwards to a purplish tinge. The prevailing colour is a greenish gray, tinged with purple. This is very bright in the young, very dull in the adult. The purple is often absent in the adult, sometimes in the young; rarely predominant. Ochre yellow sometimes prevails, in the young beautifully shaded into purple or white. The white variety is tolerably common, with gradations into the other colours ; and often with irregular rays from the umbo to the anterior margin, which is but rarely seen in D. punctatostriatus. The same colours intensified are seen in the young shells, and noted by Hanl. in his description of D. culter. In these the changes in form are extraordinary ; some being nearly triangular, while others take an extremely elongated form, with a posterior ventral sinua- tion (D. culter, var. a, Hanl.) ; but the intermediate forms are so various that I have not been able to separate them. The middle stage of growth of the gibbous form is D. contusus, Rve., aspecies described from a single specimen in the Cumingian Collection. The surface of the shell is punctatostriate ; with the dots finer and the rows further apart than in the last species. Towards the ventral part they generally subside into plain strie. On the anterior part, they are often crowded and irregular, having jagged edges or running into little lines which are sometimes confluent. A large lunular portion is smooth. The general aspect of the shell is rather glossy, especially in the young shells. The form contusus often retains the margin marks one after another, giving the shell a tiled appearance. Having examined every specimen under the glass, 1am unable to note any constant characters in the markings co-ordinate with the changes of form and colour. The crenations are gene- rally simple, without the broad marginal band conspicuous in D. punctatostriatus, and not shewing the intricate markings at the anterior end. Ihave observed no specific differences in the interior: the teeth and impressions are as in D. punctato- striatus, making allowance for the greater or less elongation of MAZATLAN BIVALVES AS) the shell: colour generally deep purple, with more or less of white. Epidermis very thin, deciduous. Umbos purple with white spot, occasionally rich orange. A transverse specimen measures long. °83, Jat. 1°52, alt. °5. A subtrigonal one 2 gE BOS, Ae), sale Doses oy ck yee The smallest i 5 #, MEE QOGR oeo5hiai4s OS.) sslannses fTab.—(D. culter) Mazatlan and Acapulco, Col. Cuming.—Maz- atlan ; common (the adult state rare, perhaps from burrowing deeper in the sand) ; LZ’ pool Col. Tablets 169—173 contain forms intermediate between this species and D. punctatostriatus.—169, 4sp. rayed.—170,°4 sp. purplish yellow.—171, 5 sp. purplish white.—172, 7 sp. yellow- ish.—173, 10 sp. more transverse. In the following series (except in the subtrigonal forms) the very young are D. culter, Hani., and the intermediate ones are generally D. contusus, Rve.: the white ones of both forms are D. Californicus, Desh. not Conr.—Tablet 174 contains 10 sp. with purple tinge predominant.—175, 9 jun. and 2 adult, very ransverse, margin sinuous, purplish gray.—176, 9 sp. less transverse.—177, regular form, 1 pair, 2 valves very young.— 178, 11 sp. very oval and regular.—179, 12 sp. less transverse, more gibbous.—180, 12 sp. very gibbous.—181, 9 sp. subtrigonal. Yellowish var: 182, 9sp. transverse.—183, 7 sp. oval, gib- bous.—184, 6 sp. subtrigonal. Greenish var: 185, 11 sp. transverse.—186, 10 sp. gibbous.— 187, 10 sp. subtrigonal. Greenish white : 188, 12 sp. very transverse.—189, 6 sp. sub- oval.—190, 7 sp. subtrigonal. Purplish white: 191, 12 sp. transverse.—192, 7 sp. subtri- gonal. White var: 193, 12 sp. very tranverse,—194, 12 sp. suboval (that marked* is curiously inequivalve with sinuous margin.)— 195, 12 sp. subtrigonal. Rayed var: 196, 12.sp. very transverse.—197, 18 sp. oval.— 198, 12 sp. subtrigonal. Tablet 199 contains 5 young shells (culter,) with the umbonal spot much developed.—200, 3 sp. (form contusus) yellowish white.—201, 3 sp. yellowish purple white. In all 292 specimens, no two being exactly alike. : Sept. 1855. ft 50 MAZATLAN BIVALVES 77. Donax navicuna, Hanl. Proc. Zool. Soc. 1845, p. 15.—C. B. Ad. Pan. Shells. p. 278. no. 456.—Rve. Conch. Icon. pl. 4, sp. 18. A eharming little species, both for its extreme beauty, and the distinctness of its characters. Shell singularly swollen, margin gibbous, scarcely shewing crenations beyond the edge at the anterior end: clothed with very glossy epidermis, be- neath which are obsolete strie. Ordinary colour greenish white, gradually assuming darker shades, often beaked with orange, generally more or less rayed, and ending in dark orange chesnut. Inside from white to fawn, ending in deep purple. Often (not always) with two streaks of purple within and without, bounding the lunular and posterior areas. It varies in the greater or less elongation, and in the ventral mar- gin which is sometimes incurved. One monster was found, shewing more prominent strie, long ‘44, lat.°9, alt. °29. Ordinary size ae Ne. Sear OOF 1 guar, eae Smallest Mawar ss ) kw al Byes wily A produced ne és se rdeel alte OT ef. oT dd, Hah—Salango and Xipixapi; in sandy mud, 9 fm ; Cuming.— Keuador ; Xipixapi, D’ Orbigny.—Panama, extremely rare ; C. B. Adams.—Mazatlan ; very common; L’pool & Havre Coll._—(T. Hindsii) Guayaquil Bay, Mus. Cuming.—(T. gra- cilior) loc. ineog.—(T. semifusca) Mazatlan, Welchers.—(T. intermedia) California, Mus. Cuming. Tablets 217—235 contain specimens arranged to shew varia- tions in form.—217, 3 sp. very transverse.—218, 3 sp. rather less.—219, 3 sp. somewhat rounded, tumid.—220, 4:sp. very regularly rounded.—221, 1 sp. ventral line flattened.—222, 1 sp. posterior part produced.—223, 1 sp. anterior part pro- duced.—224, 3 sp. gibbous.—225, 3 sp. subtriangular.—226, 4 sp. and a valve, subtriangular, produced anteriorly.—227, 1 sp. extreme form, flat, gaping,—228, 1 sp. with ecrenations outside, as sometimes in Gnathodon trigona.—229, 1 sp. dis- torted growth, gaping extremely.—230, 1 sp. mantle cut. MAZATTAN BIVALVES 57 White or very faintly streaked variety.—Tablet 231 contains 4sp., regular form, various ages.—232, 1 sp. flattened, round- ed.—233, 1 sp. produced ventrally.—234, 1 sp. transverse, gaping posteriorly.—235, 1 sp. very transverse. Tablets 236—241 are arranged to shew transitions of colour ; but many of the specimens are also remarkable for form.— 236, 3sp. white, with very faint brown markings.—237, 3 sp. brown rays narrow, interrupted.—238, 2 sp. very narrow and numerous rays.—239, 3 sp. with broad, sharp rays.—240, 3 sp. brown predominant.—24l, 3 sp. diffused brown. Tablet 242 contains 6 pairs, extremely young, which pro- bably belong to this species. Tablet 243 contains 2 young valves, which may belong to the transverse white variety. 84. TRIGONA HUMILIS, 7. s. T. t. guniore ovali, tinbonibus appressis; ?adulta parva, subtrigond,- margine ventrali excurvd, lata&; umbonibus non wncurvis, parum prominentibus ; levi, vel striis incrementi exili- bus: fusca, intus maculo purpureo dente postieo; dent. lat., antico brevi, solido, postico longo, exili ; card. 2-8 parvis ; lined pallii a margine remota, sinu parva, subascen- dente ; ligamento celato, brevi ; epidermide tenut. This shell might be taken for the young of Dione chionea, but for the entire absence of spirally recurved umbos ; it differs also from the shells supposed to be the young of T. radiata in the flatness of the umbos and the comparatively small size of the teeth. Not being able to affiliate it with any satisfaction, I have been compelled to describe it provisionally. In the youngest stage only the lateral teeth are prominent, and the shape is almost oval; then the anterior tooth turns round and makes a cardinal, and afterwards the other cardinal teeth ap- pear. There seems always a stain of purple inside the ligament. When adult, it becomes subtrigonal, with the dorsal margins rather straight. Neither lunule nor area are defined. The youngest specimen measures Jong. °02, Jat. ‘035, al#. °O15. The largest ou GY ao Aiea sam ne Hab—Mazatlan ; rather uncommon, in Spondylus and Chama washings ; L’pool Col. Tablet 244 contains 2 pairs united, and 4 pairs of valves of different ages. 58 MAZATLAN BIVALVES 85. TRIGONA ARGENTINA, Sow, Cytherea argentina, Proc. Zool. Soc. 1835, p. 46.—Hanl. Descr. Cat. p. 105:— Wood's Suppl. pl. 15, f. 15.— Phil. Abbild. Conch. Cyth. pl. 3, f.5.—Sow. Thes. Conch. p. 622, pl. 129, f. 62.—? Menke Zeitsch. f. Mal. 1847, p. 189, no. 55. Trigona argentina, Desh. B. M. Cat. Ven. p. 50. no. 16. This shell may be known at once from those varieties of T. radiata which most approach it by the very remarkable and constant shape ; being most regularly excurved along the ven- tral margin, incurved on the anterior and straight on the pos- terior dorsal lines. Colour dull white, with light olive green epidermis ; often with two rays of violet within. The anterior cardinal tooth is much larger than in T. radiata, and the pos- terior tooth does not display rugose sulcations. The anterior adductor sear is less deeply impressed and more evenly bounded. Long. 2°12, lat. 2°6, alt. 1°52. Hab.—Gulf of Nicoyia, in sand banks at low water, Cuming.— ?Guaymas, Lieut. Green, (Gould ms.*).—Mazatlan; Mel- chers.—Do. very rare; L’pool & Havre Coil. Tablet 245 contains 3 minute valves, the smallest ‘04 across, which may belong to this species. Tablet 246 contains 2 specimens. The smallest displays the violet rays, and an abnormal lamina within. 86. TRIGONA P? CRASSATELLOIDES, Conr. Ann. Nat. Hist. Soe. Philad. t. 7, p. 253, pl. 19, f. 17.— Hinds, Voy. Sulph. Moll. p. 65, pl. 21, f. 1.— Desh. B. M. Cat. Ven. p. 46, no. 1. Cytherea crassatelloides, Hanl. Deser. Cat. p. 106 :— Wood Suppl. pl. 15, f. 32.—Sow. Thes. Conch. p. 612, pl. 127, f. 1—3. Tablet 247 contains 2 small valves, (the smallest *04 across) which have the shape aud thickness of this species. Their identity however is doubtful, T. crassatelloides belonging strictly to the Californian fauna, where it attains a diameter of 5inches. (Woodw. Nutt.) * Dr. Gould writes ‘‘ Venus straminea, Conr. = argentina P” Tapes straminea, Conr. is the Californian representative of T. histrionica or T. grata. Itis pro- bable therefore that our shell is meant, as Tr. argentina is a well known and constant form. It is possible however that it may not be known to Gould, and uel the oe shell is meant: also that Menke’s Cytherea argentina is one form of T, radiata, MAZATLAN BIVALVES 59 Hab.—Sta. Barbara; Nuttall, Col. Jewett—San Diego; Lieut. Green.—Mazatlan ; Lieut. Green. (Gould ms.)—?? do; from shell washings ; L’pool Col. 87. TRIGONA PLANULATA, Brod. & Sow. Cytherea planulata, Zool. Jowrn. vol. v. p. 48.—Sow. Gen. f.2.— Rve. Conch. Syst. vol. i. p. 94, pl. 69, f.2.—Hanl. Deser. Cat. p- 105.—Zool. Beech. Voy. p. 151, pl. 43, f. 6.—Sow. Thes. Conch. p. 618, no. 20, pl. 127, f. 13. Venus planulata, B. M. Cat. D’ Orb. Moll. p. 66, no, 587. Trigona planulata, Gray Cat. Cyth. Anal. yol. viii. p. 304— Desh. B. M. Cat. Ven. p. 48, no. 8. + Var. suffusa, Sow. Proc. Zool. Soc. 1835, p. 46. + Cytherea undulata, Sow. Thes. Conch. p. 618, no. 21, pl. 127, f. 12.—(Trigona u.) Desh. B. M. Cat. Ven. p. 48. no. 9. = Donax Lessoni, Desh. Enc. Méth. vers. t. 2. p. 99. =(teste Desh.) Cytherea mactroides, Lam. (non Born nee Sow.) An. s. Vert. vol. vi. p. 307, no. 27.—Deless. Rec. de Coq. pl. 8, f. 2.—Hanl. Descr. Cat. p.99: Wood Suppl. pl. 13, f. 17. The very, illustrious Deshayes in his later works seems much more disposed to the multiplication of species than he was in his earlier edition of Lamarck. He follows Sow. jun. in divid- ing the C. planulata of Brod. & Sow. The C. undulata is discriminated by its more equal form, greater solidity, absence of posterior gape, distinctness of lunule and style of painting. I have not found any one of these characters constant. The species varies almost as much as its more swollen congener, T. radiata. In form there is a gradual passage between the two. The undulate are if anything thinner than the planulate. The breaking up of the coloured rays proceeds by insensible gradations, and the colouring of the interior varies greatly. The gaping is either posterior, or anterior, or both, or some- what ventral, or none, just as it happens. The beaks are scarcely ever tipped with purple. The painting of the two valves does not always correspond. The teeth are very small and angular ; anterior lateral much prolonged. The W. African analogue is T. bicolor, Hani. Typical form measures long.2°, Jat. 2°3, alt. 1°. Var. undulata __,, 5p UPS Ta Ow Tle Ray Hab.—Panama, Cuming—Chili; Coquimbo; D’ Orbigny.— Found abundantly near Mazatlan; Lieut. Belcher —Maz- atlan; not common; L’pool Col.—Var. suffusa; Salango, sandy mud, 9 fm. Cuming.—Var. undulata, do. Cuming. 50 MAZATLAN BIVALVES Tablet 248 contains 3 young specimens, dull ash colour, slightly rayed, one with slight gape.—249, 1 sp. adolescent, closed, slightly rayed on one valve, the other mostly dull brown.—250, 1 sp. larger, closed, margin waved.—251, 1 fine adult sp. gaping posteriorly and ventrally.—252, 2 sp. very slightly gaping, rays clouded.—253, 1 do., form undulata, gap- ing nearly all round.—254, 2 do. form and colouring intermedi- ate; one gapes posteriorly, the other ventrally.—255, 2 pairs and 2 valves, form undulata, large posterior gape.—256, 3 do. valves closed; of which one is nearly white inside, another of a rich diffused violet. Similar differences of colour may be . observed in the other specimens. Genus DOSINIA, Scopoli. Dosinia, Scop. Intr. ad Hist. Nat. p. 399, (1777).— Desh. B. M. Cat. Ven. p. 5. Artemis, Poli, Test. utr. Sic. p. 98, t. 1. (1791). 88. DosIntA PPONDEROSA, Gray. Artemis ponderosa, Gray Anal. (1838), vol. vii. p. 309.— Rve. Conch. Icon. pl. 1. f. 4.—Hanl. Descr. Cat. p. 109, pl. 19. f. 38.—Sow. Thes. Conch. p. 656, no. 3, pl. 140, f. 2. Dosinia ponderosa, Desh. B. M. Cai. Ven. p. 7, no. 5. Cytherea gigantea, Phil. Abbild. Conch. Cyth. p. 33, pl. 7, f. 1. DANO. 1 . Venus cycloides, B. WM. Cat. D’ Orb. Moll. p. 67, no. 596. A single specimen in beautiful condition, after being referred to D. econcentrica (Gulf of Mexico), and D. distans (unknown ; probably Puerto Portrero), was at last doubtfully affiliated to this species by Mr. Cuming. A larger specimen procured since from another dealer, and probably from the same collec- tion, confirms the judgment. It is remarkable for the very orbicular form, slightly angulated beyond the ligament ; deeply cut lunule; and very regular and distant sulei, not obsolete in the middle, of which, measuring from 1 to 1°5in. from the umbo, there are only 8. The epidermis is extremely glossy, of a very light straw colour. Long. 1°64, lat. 1°74, alt. °73. Hab—Gulf of California, in sandy mud at low water, Sowerby. —Peru; Payta, D’ Orbigny—Mazatlan ; extremely rare; LP’pool Coil. Tablet 257 contains the specimen. MAZATLAN BIVALVES 61 89. Dosinta ANNA, 2. 8. D.t. compressa, elongatiore, marginibus equaliter arcuatis : suleis concentricis subdistantibus, haud impres- sts, medio subobsoletis ; lunuld oblonga, subimpressa ; lacted, epidermide flavescente, medio tenuissimad ; dentibus haud valde diwergentibus : sinu pallu haud magno, angulato, apice ad marginem ventralem muse. adduct. ascendente. This fine , and (for a Dosinia) well marked species is known from D. ponderosa by its greatly elongated form; from D. Dunkeri by its larger size, flatter growth, smoother ribs (the difference being at once perceived by drawing the nail along the two shells) which are obsolete in the middle ; and especially by the shape of the pallial sinus, which in D. Dunkeri almost always points to the middle, in this towards the ventral edge of the anterior adductor. Long. 2°44, lat. 2°35, alt. 1°12. fab.— Mazatlan ; very rare; L’pool Col. Tablet 258 contains a young and a full grown specimen. 90. Dosinta Dunxert, Phil. Cytherea Dunkeri, Phil. Abbild. Conch. Cyth. p. 4. no. 5. pl. 2, f. 9. (Oct. 1844.) ; Artemis Dunkeri, ve. Conch. Ic. pl. 6, f. 34.—Ad. & Rve. Voy. Samarang, p. 78, pl. 21, f. 17.—Sow. Thes. Conch. p. 657, “ no. 7, pl. 140, f.5.—C. B. Ad. Pan. Shells. p. 274, no. 448. Dosinia Dunkeri, Desh. B. M. Cat. Ven. p. 8, no. 9. =Artemis simplex, Hanl. Proc. Zool. Soc. Jan. 1845, p. 11: Descr. Cat. Ap. pl. 19, f. 41.—Rve. Conch. Ic. pl. 10, f. 9.— Sow. Thes. Conch. p. 657, no. 8, pl. 140, f. 6.—(Dosinia s.) Desh. B. M. Cat. Ven. p. 9, no. 11. Cytherea Pacifica, (Mus. Berol.) Trosch. in Wiegm. Archiv. p. 324, (non Dillw.) After very patient but altogether ineffectual attempts to separate D. simplex of the monographs from D. Dunkeri, in the many hundred specimens which have passed under review, I am imformed by Mr. Hanley himself that his species is the same as Philippi’s; and as the name of the latter bears date a few months earlier, it is necessary to preserve it. The shell is known by its very rounded, inflated form, more or less produced ventrally ; the more produced form is the D. simplex of the monographs. It varies somewhat in the closeness of the striz, Sept. 1858. g 62 MAZATLAN BIVALVES but with these exceptions is tolerably constant in character, eee white, with thin light straw-coloured or yellowish epi- ermis. A typical specimen measures long. 1°73, lat. 1°76, alt. 1°04. A produced ,, . H iy Se as na amines Ha tage a Hab.—Pacific shores of Mexico, Philippi.—Panama, St. Elena, Mus. Cuming, (Hanl.)—Panama, not common, C. B. Ad- ams.—Kastern Seas, A. Adams.—Mazatlan ; very common ; ‘pool & Havre Coll. Tablet 259 contains 5 young specimens, the smallest ‘Si > across.—260, 5 do. adult.—261, 5 do. jun. closer strize.—262, 5 do. adult.—263, 6 sp. distant striz.—264, 5 sp. adolescent, produced form.—265, 4 do. adult. / Genus CYCLINA, Desh. Cyclina, Desh. Traité Elém. (1849) 1. pl. 14 bis, f. 20—22.— B. M. Cat. Ven. p. 29. ‘ As the animal of this genus is said by Gray to be like Dosinia, while that of Lucinopsis (Forbes & Hanl. Br. Moll. 1848, vol. i. p. 433) 1 is very different, being closely allied to the Tellinide, (Clark k, Moll. Test. Mar. Brit. pp. 182 et seq.) both genera will have to be preserved; and the location of different species must await our knowledge of their animals. 91. Cychina suBquaDRaATA, Haul. Artemis subquadrata, Proc. Zool. Soc. 1845, p. 11 :—Descr. Cat. App. pl. 15, f. 39—Rve. Conch. Icon. pl. 3, f. 15.—Sow. Thes. Conch. p. 661, pl. 141, f. 27. Lucimopis subquadrata, P. P. C. Cat. Prov. Cyclina subquadrata, Desh. B. M. Cat. Ven. p. 31, no. 4. =Arthemis saccata, Gould, Proc. Bost. Soc. Nat. Hist. 1851, p. 91:—Meex. & Cal. Shells, p. 23, pl. 15, f. 2—(Artemis s.) C. B. Ad. Pan. Shells, p. 275, no. 449.—Cyclina s.) Desh. B. M. Cat. Ven. p. 32, no. 9.* This shell agrees in form and muscular impressions with Lucinopsis, but the teeth are those of Cyclina. The young shell is much more orbicular in form. I picked a valve from a col- lection of W. Indian shells which exactly resembles this species in all respects except the anterior muscular impression, which * Having just received the {type specimen of A. saccata, through the great kindness of Dr. Gould, I can speak to its exact identity. MAZATLAN BIVALVES 63 1s somewhat nearer to the hinge, with the sinus less ascending. Epidermis extremely thin. Long. 1°51, lat.1°54, alt. ‘8. Hab.—St. Elena, West Columbia [?] very rare, Mus. Cuming. (Hanl.)—Panama, extremely rare; C. B. Adams.—Mazat- lan; Lieut. Green.—Mazatlan, extremely rare; L’pool Col. Tablet 266 contains the largest specimen. Genus DIONE, Megerle. Dione, B. M. Cat. Ven. p. 54. =Cytherea (maxima pars), Lam. Known by the smooth posterior teeth, ovate transverse form, and large horizontal pallial sinus. 92. Dione aurantia, Hanl. Cytherea aurantia, Hanl. Sp. of Shells, Append.: Wood Suppl. pl. 15, f. 20.—Sow. Thes. Conch. p. 228, pl. 132, f. 97 bis. Chione aurantia, Gray, Analyst, viii. 305. Dione aurantia, Desh B. M. Cat. Ven. p. 56, no. 3. Cytherea aurantiaca, Sow. Gen. f. 3.— Rve. Conch. Syst. pl. 69, f, 3.—Jay’s Cat. p, 35.—C. B. Ad. Pan. Shells, p. 272, no. 44A. This magnificent and typical species appears to belong to the N. W. tropical province. The shape in regularity more nearly coincides with D. chione than with D. chionea. It is however larger and heavier; less transverse, lunule less marked, and shewing a tendency to irregular concentric ridges of growth. The trifureate white mark at the umbos has shorter and broader rays. The colour is a light salmon with occasional concentric bands of darker, in the young shell generally white at the margin; covered with a uniform, rather thin, adherent, dark orange epidermis. Inside white, with purple stain on the liga- mental portion. Anterior adductor deeply impressed: the rest nearly as in D.chione. I have not been able to trace Sow.’s “obscure biangulato, &c.”’ copied by Desh. Long. 3°62, lat, 4°28, alt, 2°37. A specimen from 8. W. Mexico is some- what larger. Hab.—Gulf of Nicoyia, Jay.—Taboga, very rare, C.B. Adams.— South America [?; non D’Orb. nee Cum.]; Acapulco; Desh- ayes.—S. W. Mexico, P. P. C—Mazatlan; Lieut. Green. — Do. not common; L’pool Col.* * **Brazil;” Manchester Mus., without authority ; probably an error, 64 MAZATLAN BIVALVES Tablet 267 contains 2 minute valves, the smallest °03, across, which may belong to this species. Tablet 268 contains 2 young specimens.—269, 2 sp. very large.—270, a distorted sp. with one valve overlapping.—271, another distorted sp. with a large anterior gape. 93. Dionr cH1onmuA, Menke.* Cytherea chionea, Menke in Zeit. f. Mal. 1847, p. 190, no. 57. Cytherea squalida, Sow. Proce. Zool. Soc. 1835, p. 23.—Hanl. Descr. Cat. p. 104: Wood’s Suppl. pl. 13, f. 40.—Sow. Thes. Conch. p. 629, pl. 131, f. 87-89.—C. B. Ad. Pan. Shells, p. 273, no. 447. Chione squalida, Gray Cat. Cyth. Anal. 1838, viii. 306. Venus squalida, B. M. Cat. D Orb. Moll. p. 68, no. 609. Dione squalida, Desh. B. M. Cat. Ven. p. 58, no. 6. + Cytherea biradiata, Gray, Zool. Beech. Voy. 1839, p. 151, pl. 43, f. 5.—Svebold. in Wiegm. Arch. + Cytherea chione, pars, Sow. Thes. Conch. p. 629, no. 59. ?=Cytherea elegans, Koch. in Phil. Abbild. Conch. Cyth. 184A. p. 2 (150) pl. 1, f. 4. For a full description of the main features of this shell, v. Cytherea chione, Forbes & Hanl. Br. Moll. i. 396—8, which applies in most of the minute particulars, even in that which is said to separate it, the 3 short ray-like colourless markings of which the central is the shortest, and the others margin the commencement of the lunule and the ligamental area. It is necsssary however to state, for the benefit of those who think * The learned have hardly behaved well to this exquisitely:beautiful species. It was first described from some Peruvian shells of a ‘‘very dull and dirty aspect,” by Sow., under the name (very inappropriate to the species generally) of C. squalida. He confesses however that one of the varieties is ‘‘ rather agreeably ornamented with concentric purple bands.” The Mazatlan shells were next described by Gray, in the Zool. Beech. Voy., as C. biradiata, a name applicable again only to a portion of the species. The East Indian shells were next named by Koch and described by Phil. in 1844s C. elegans. Then Sow. jun. in 1851 gives in quo- tations (as though from the P. Z.S.) a fresh description of C. squalida, with only 6 of the original words, adding with singular inappropriateness ‘‘rubente- albicante radiata ; costellis numerosis, concentricis, obtusis, econcinnis, confertis.”” He also tells us (an error which C. B. Ad. very politely exposes) that the species was first named from Philippine specimens brought by Mr. Cuming; and also that the name OC. biradiata in Beechey’s voyage was given to the Philippine shells. Not content with these errors, he also informs us that Mr. Cumings’s Mazatlan specimens belong to the Europzan C, chione.—Last of all Menke gives the name C. chionza to the Mazatlan species; and though he only describes from a single specimen, it fortunately happens that both name and description are sufficiently comprehensive. As the prior names only apply to portions of the species, the ordinary rules of priority are disregarded in order to retain an expressive name which includes the whole species. MAZATLAN BIVALVES 65 that Cytherez may always be known by the umbonal markings, that in this species they are extremely variable: the white rays take very different directions: or it is not rayed at all: or the white is entirely absent. The colour varies from dark lustrous brown to light grey : sometimes uniform, often biradi- ate with dark brown, generally more or less spotted in the young shell; occasionally tinged concentrically with red, very rarely with purple or greenish, but never with the reddish chesnut which is very characteristic of D. chione. The inside also is often stained with violet, occasionally with yellow. The principal difference from D. chione is the shape, which is more swollen, almost subangulated in the posterior dorsal portion, the angular line generally ending in a produced posterior margin. These characters however are not constant. There is a spotted variety rather hard to distinguish from its W. In- dian analogue, D. maculata, not being less tumid (as Sow: states,) but rather more, and losing the posterior angulation. The pallial sinus in D. chione is generally defined by a some- what broader line, and is a little more pointed ; though I found the shape.vary not a little in the many hundred specimens of D. chionza which I have carefully examined. The East Indian specimens (if Philippi’s figures are correct) have the ligament rather shorter, the lunule longer, and the pallial sinus less angulated. In other respects they exactly agree, and are considered identical by the very accurate Desh. ; not, of course, for geographical reasons, by C. B. Ad. If dis- tinct, they will take Koch’s name of D. elegans. If I have rightly affiliated certain very small valves, the young shell (of which the smallest measures only *02 across) first developes the marginal teeth, leaving the central ones till it gets older. The anterior portion of the shell also is of abnor- mal size. The longest specimen measures long. 2°77, lat. 3°58, alt.1°6. A transverse specimen ,, Bde op De OM arrestin Alone topuwe bees A rounded specimen ss fy Mids GBs bi ST ae Hab.—St. Elena, in sandy mud, 6 fm., Ouming.—Ecuadar : St. Elena, D’ Orbigny.—Taboga, very rare, C. B. Adams.— La Paz, Lieut. Green—S. W. Mexico, P. P. C.—Found abundantly at San Blas and Mazatlan, Lieut. Belcher.— Mazatlan, common; L’pool & Havre Col.—(D. elegans) Philippines, Cuming.—Swan River, N. H., Philippi. Tablet 272 contains 11 small perfect and imperfect valves which probably belong to this species. 66 MAZATLAN BIVALVES Tablet 273 contains 7 sp. of various ages, biradiate.—274, 2 do. gibbous.—275, 2 do. uniform dark brown.—276, 1 do. trans- verse, very dark brown.—277, 6 do. and 2 valves, rather dark, not biradiate.—278, 6 do. light gray.—279, 3 do. very light, faint rays, young shell speckled.—280, 2 do. greenish tinge.— 281, 1 do. purplish.—282, 4 do. concentrically banded with reddish.—283, 4. do. and a young valve, spotted, form like D. maculata. 94. DionE roses, Brod. & Sow. Cytherea rosea, Zool. Journ. iv. 364.—Zool. Beech. Voy. Moll. p. 151, pl. 43, f. 7—Hanl. Descr. Cat. p. 104: Wood's Suppl. pl.9, f. 11.— Pil. Abbild. Conch. p. 183, pl. 5, f. 6.—Sow. Thes. Conch. p. 632, p. 132, f. 108. Dione rosea, Desh. B. M. Cat. Ven. p. 77, no. 71. Cytherea lepida, Chénu, Conch. Ill. Shell as usual, either more or less produced posteriorly, or swollen ventrally ; but in all varieties known from D. lupinaria 1. by the non-development of spines, which alone might be accidental ; 2. by the shape, which is much flatter, and gener- ally more produced ventrally ; 3. by the colour, in which pink- ish brown rather than purple predominates, being uniform over the whole shell; a white streak going along the line of spines without purple at the bases, and a brownish instead of purple patch covering the lunular portion; 4. by the anterior lamine, which instead of being close together, are only raised here and there, generally at intervals of 4 or 5; 5. by the longer ligament, which is enclosed by a finer ridge, scarcely conspicuous in one valve; 6. by the absence of the line mark- ing the second row of spines and angulating the posterior margin; 7. by the teeth which are less raised, more spreading. The colour within is white with diffused violet,not predominant at the hinge. Extremely rarely there is an attempt at the formation of a knob or two where the second row should be, but never a marking line. The concentric ridges are fine, nearly equal, and rarely evanescent ventrally. The ridge which bears the raised lamina does not necessarily bear the raised knobs. The ridges sometimes bifurcate, but are generally more parallel to the margin than in D. lupinaria. I have examined above 500 specimens, in which I believe the above characters are constant. A large number of them are pierced by preda- cious gasteropods. MAZATLAN BIVALVES 67 The largest specimen measures long. 1°97, lat. 2°38, alt. 1°06. A transverse specimen _,, ait whites tis eaCdds yeep Hab.—Found abundantly at San Blas, Lieut. Belcher, (Beech. Voy.)—Panama, Cwming (teste Sow.: non C. B. Ad.).— Mazatlan ; abundant ; L’pool & Havre Col. Tablet 284 contains a minute valve, probably belonging to this species, measuring ‘06 across. Tablet 285 contains 7 specimens, normal type.—286, 5 do. dark coloured, transverse.—287, 3 do., brownish tinge.—288, 3 do. lamine slightly raised; the largest was attacked by a gasteropod, who left his hole unfinished.—289, 3 do. pinker shade.—290, 3 do. more produced ventrally.—291, 3 do. most produced.—292, 3 do. coarse ribs.—293, 3 do. very pale. 95. Dione Lupinaria, Less. Cytherea lupinaria, Less. Cent. Zool. p. 196, pl. 64.—Sow. Thes. Conch, p. 632, f. 111. Venus lupanaria, B. MZ. Cat. D’ Orb. Moll. p. 67, no. 593. Chione lupanaria, Gray Anal. viii. 306. Dione lupanaria, Desh. B. M. Cat. Ven. p. 76, no. 68. Cytherea Dione, var. Brod. Proc. Zool. Soc. 1845, p. 45-6.— Gray in Griff. Cuv. An. King. pl. 19, f. 1.—Rve. Conch. Syst. moo: ple Wily fds Cytherea semilamellosa, Gawd. in Deless. Ree. pl. 19, f. 2.— Chénu. Conch. Lil. pl. 9, £. 9. This shell is sometimes shaped like its well known W. Indian analogue, V. Dione, Zin. (Dione Veneris, Desh.): but is almost always larger and more transverse. It is known at once by the concentric ridges, which are never sharp and raised as in D. Veneris, but either rounded or sub-obsolete on the ventral part. Many of them (generally every other, or 1 out of 3) become obsolete before reaching the anterior part ; the remain- der become sharply lamellar, gradually fading off to the lunule, not suddenly ending there asin D. Veneris. The posterior part has two angular swellings, one in the line of the inner spines, the other just beyond the ligament. The inner area, lunule and bases of spines are almost always purple even in the pale variety. There are all shades of colour from white to rich puse or purple. The spines appear very irregularly, sometimes two or more growing together, sometimes leaving a large space without. The young shell has always two rows, 68 MAZATLAN BIVALVES the inner one turned backward. In the adult, this row ceases. The very young shell has none; while in D. Veneris they ap- pear much earlier. The spines in the large row are generally rather straight and very long; one measured long. 1°88, and others must have been longer when perfect. The concentric ridges are not always parallel with the margin of the shell, and often bifurcate very irregularly. I have examined carefully nearly 4,000 specimens, almost all of which had fallen victims to the voracious appetites of gasteropods, who drill their holes . generally near the apex. Epidermis extremely thin: spines channeled. The spine of the smallest well marked specimen measures “41; the shellitself long. °49, Jlat.°59, alt. ‘31. The largest (without spines) Wh. PE DOs ees eh de oes oe The most transverse 53). bare. eo ty 4, dese Hab.—Salango, in sandy mud, 9 fm. ; Tumbez (Peru) soft mud, 5fm.: Cuming—San Blas (Culf of California), sandy mud, 7 fm., Col. Cuming.—Payta, (Peru,) D’ Orbigny.— Mazatlan ; Col. Jewett, (Gould ms.)—Do; extremely abundant, L’pool &§ Havre Coll. Tablet 294 contains 2 minute valves, (the smallest ‘025 across,) which probably belong to this species, though they shew no trace of spines. Tablet 295 contains 9 very young specimens, rounder form, with rather coarser striz.—296, 6 do. rather older.—297, 3 do. adolescent.—298, 2 do. very large.—299, 9 very young, trans- verse form.—300, 8 do. rather older.—301, 6 do. adolescent.— 302, 3 do. adult.—303, 5 young, pale var.—304, 3 do. adult.—305, 4 sp. with extra spines.—306, 1 large do. shewing epidermis.— 307, 3 young, spines forming at margin.—308, 3 do. spines strangely curved.—309, 2 do. small spine growing by and in broken large one.—310, 1 adult, with spurs on bottom of spines.—311, 1 do. two spines growing together.—312, 1 do. very crowded spines at margin. In all, 72 specimens. 96. Dione ? vuLNERATA, Brod. Cytherea vulnerata, Proc. Zool. Soc. 1835, p. 46.—Hanl. Deser. Cat. p. 105.—Catlow. Cat. p. 40, no. 116.—Sow. Thes. Conch. p. 632, pl. 131, f. 95, 96. Dione vulnerata, Desh. B. M. Cat. Ven. p. 60, no. 15. Tablet 313 contains 2 minute opposite valves which may belong to this species. Hab.—Real Llejos, in sandy mud, 6 fm. Cuming.—? Mazatlan ; 2 valves off Spondylus ; L’pool Col. MAZATLAN BIVALVES 69 97. DionE ? BREVISPINOSA, Sow. Cytherea brevispinosa, Sow. Thes. Conch. p. 632, pl. 132, f. 109. Dione brevispinata, Desh. in B. M. Cat. Ven. p. 76, no. 70. Tablet 314 contains a minute valve which may be the young of this species. It has close concentric rounded ribs, and very strong teeth for the size. Length ‘03. Hab.— Gulf of California, Col. Cuming.—? Mazatlan, jun. 1 valve; L’pool Col. > 98. Dione crrcinatTa, Born. Venus circinata, Born, Test. Mus. p. 61, pl. 4, f. 8.—Chemn. Conch. Cab. vi. 312, pl. 30, f. 311.—_Dillw. Rec. Sh. i. 169.— B. M. Cat. Sagr. Moll. p. 39, no. 474. Cytherea circinata, Sow. Thes. Conch. p. 631, pl. 132, f. 104-6.— Horbes & Hanl. Br. Mol. i. 399. Dione circinata, Desh. B. M. Cat, Ven. p.77, no. 72. Venus Guineensis, Gimel. Syst. Nat. p. 3270, &ce. Cytherea Guineensis, Lam. An. s. Vert. ed. Desh. vi. 311, &e. Cytherea alternata, Brod. Proc. Zool. Soc. 1835, p. 45. Tablet 315 contains a small white valve which may be the young of this species: long. ‘08, lat. °095, alé. 05. Hab—Cuba, Sagra.—S. Atlantic, Forbes.—Mazatlan, Capt. Donnel :—do. Lieut. Green, (Gould ms.) :—do. one valve and fragments, jun., L’pool Col.—Var. alternata, Monte Christi, in sandy mud, 11 fm., Cuming. . 99. DionE conctnna, Sow. Cytherea concinna, Proc. Zool. Soc. 1835, p. 23.—Sow. Thes. Conch. p. 630, pl. 132, f. 99, 100. Dione concinna, Desh. B. M. Cat. Ven. p. 74, no. 61. Comp. D. affinis, Brod. Proc, Zool. Soc. 1835, p. 45; B. M. Cat. Ven. no. 60: and D. tortuosa, Brod. id.; B. M. Cat. Ven. no. 62. This shell is coloured in sienna brown and white stripes in about equal proportions, the brown being darker on the ribs and in the lunule. Umbos yellow. Concentric ribs occasionally bifurcating. Pallial sinus, long, narrow, ascending. Long. 1°2, law lige. le. "75. Hab.—Panama, in fine sand, 10 fm. Cwming.—Mazatlan ; 1 sp. with D. rosea; LZ’pool Col. Tablet 316 contains the specimen. 70 MAZATLAN BIVALVES Genus CYTHEREA, Lam.* Cytherea, ex parte, Lam. 1809, et auct. Meretrix, Lam. 1799; Desh. B. M. Cat. Ven. p. 34. This genus, as restricted, is known by the subtrigonal form, crenated posterior and distant anterior tooth, and the very small pallial sinus. 100. CYTHEREA PETECHIALis, Lam. Lam. An.s. Vert. ed. Desh. vol. vi. p. 299.—Sow. Gen. f. 1.— Hanl. Descr. Cat. p. 96 :—Wood Suppl. pl. 15, f. 9.—Rve. Conch. Syst. vol. i. pl. 69, 70, f. 1.—? Sow. Thes. Conch. p. 619, pl 129, £51. Meretrix petichialis, Hnac. Méth. pl. 268, f. 5, 6.—Desh. B. M. Cat. Ven. p. 36, no. 4. The widely extended form to which this shell belongs was distributed by Lam. under the species lusoria, petichialis, im- pudica, castanea, zonaria var. 1, meretrix and graphica.—Desh. in his edition of Lamarck regarded the 6 last, and C. lusoria probably, as all varieties of one species, differing only in colour, and displaying insensible gradations even in this. In the B. M. Cat. Ven. however he publishes them all as distinct (ex- cept meretrix which is merged into M. impudica), along with C. fusea, Koch in Phil. Abbild. Conch. p. 19, pl. 3, f. 1.—Sow. unites C. graphica with C. petichialis, C. fusca with C. lusoria, C. castanea with C. impudica, adding C. formosa on his own authority, and yet “‘being almost persuaded that” all these, along with C. meretrix, morphina, zonaria, casta and ovum Hani., “might be united under one name, seeing that they pass imperceptibly into each other, and that in a young state it is almost impossible to distinguish them.” If the varieties would arrange themselves into zoological provinces, there would be more hope of finding specific types ; but Iam unable to find any difference between the Mazatlan shells and those from the China and Japan seas. I found scarcely a dozen specimens in the D. chionea box of the Liverpool collection ; but several more were seen mixed with the other Mazatlan shells in the shop of a dealer who had surreptitiously obtained * The familiar Lamarckian name (‘‘nom plus convenable,’’ Lam.) is retained, because a man ought to be allowed to alter his own work if he can improve it ; as he certainly did in this instance, by rejecting a meretricious name for so beau- tiful a group of shells, There is nothing unchaste in nature: it is only man’s corrupt ideas that see unclean images in the purity of God’s works. MAZATLAN BIVALVES . 7 no inconsiderable a portion of the collection.* These shewed great diversities of colouring; sometimes abounding in the typical dots, sometimes shewing the faintest traces of them. The dots were scarcely ever angulated, according to the de- scription and figures of Sow. The favourite trifurcate white mark at the umbos sometimes darts up long angular rays ; in other cases it is extremely small and irregular. Long. 2°5, lat 2°9, alt. 1°4. Hab.—Indian ocean, Lamarck.—China, Deshayes.—[? C. gra- phica] Japan, Dr. Sibbald, Mus. Cuming.—Mazatlan, very rare; L’pool Col. Tablet 317 contains 5 young valves, from the Chama and Spondylus washings, the larger of which I think certainly, the rest perhaps, belong to this species. Tablet 318 contains 2 adult specimens, one of which at least was from the box. Genus VENUS, Linn. Venus, ex parte, Linn., Lam., et auct. Chione, Megerle, 1811; Gray, 1847; Desh. B. M. Cat. Ven. p. 118; (non Gray, 1838.) 101. Venus (Curong) entpia, Brod. & Sow. Venus gnidia, Zool. Journ. iv. 364.—Rve. Conch. Syst.. pl. 68, f.5.—? Gray in Zool. Beech. Voy. pl. 41, f.3.—Deless. Rec. de Coq. pl. 19, f.1, a, b—Hanl. Deser. Cat. p. 113, pl. 13, f.43: Wood's ‘Supol. pl. 13, f. 483.—Sow. Phes. ce p. 709, pl. 154, f. 25.—B. M. Cat. D Orb. Moll. p. 68, no. 606.— C. B. Ad. Pan. Shells, p. 269, no. 437. Chione gnidia, Desh. in B. M. Cat. Ven. p. 132, no. 41. This queen of Veneres flourishes in the greatest luxuriance and magnificence in the Mazatlan seas. Though the texture is not so delicate as that of Ch. amathusia, nothing can exceed the beauty of the concentric frills, which rise at various intervals generally perpendicular to the surface of the shell. On the back, they carry off the radiating furrows: on the front they are beautifully crenated. They generally rise into lamine (sometimes *23 long) which are occasionally bent up almost * Before I knew how much the species was divided, I distributed under this name in several of the Mazatlan collections (‘‘ Hab. incog.’’) specimens which properly rank under one of the other groups. i2 MAZATLAN BIVALVES into atube. The epidermis is extremely thin, but important to preserve the shell, which soon becomes of a calcined appear- ance without it. The radiating striz become obsolete in the old shells, but not so much so as in Ch. amathusia. The smallest valve measures ‘03 in length: the largest specimen, Jong. 3°5, lat. 3°56, alt. (without spines) 2°3. Hab.—Payta, Peru, Fontaine, D’Orbigny.—Panama, rare, C. B. Adams.—San Blas, Jay.—Mazatlan; Lieut. Green, (Gould ms.) ; extremely abundant; L’pool & Havre Coll. Tablet 319 contains 3 very young valves.—320, 4 young specimens, form somewhat rounded.—321, 3 do. adolescent.— 322, 3 do. adult.—323, 3 young, slightly produced.—324, 3 do. adolescent.—325, 2 do. adult, ribs close.—326, 3 do. young, more produced.—327, 2 do. adult.—328, 4 young, rather flat- tened, with distant laminz.—329, 3 do. adolescent.—330, 2 do. adult.—331, 5 young specimens set to shew the ventral margin in different stages of growth.—332, 4 do. adolescent.—333, 4 do. adult.—334, 2 sp. shewing the nearest approach to Ch.amathusia, and unnatural longitudinal grooves.—335, 1 sp., ribs not foli- ated ventrally.—336, 2 do., ribs flattened.—337, 1 do., strongly foliaceous.—338, 1 do., foliations semispinous.—339, 1 sp. de- formed growth.—340, 3 do. with irregular ribs. In all 59 specimens. 102. Venus (CHIONE) AMATHUSIA, Phil. Venus amathusia, Phil. Abbild. p. 129, pl. 2, f. 4.—C. B. Ad. Pan. Shells, p. 269, no. 435.—Sow. Thes. Conch. p. 709, pl. 154, f. 26, 27. Chione gnidia, var. Desh. B. M. Cat. Ven. p. 133, no. 41. + Chione amathusia, Desh. do. p. 132, no. 39. P= Venus cancellata, Menke in Zeit Ff. Mal. 1847, p. 191, no. 58, (non Lam.) P= Venus succincta, Val. in Humb. Rec. d’ Obs. vol. ii. I follow Hank Sow. and ?C. B. Ad. in regarding this as Philippi’s species. It agrees exactly with the description ; not with the figure. I have however avery worn young stumpy specimen from S. W. Mexico, which is sufficiently like the figure, especially when it is remembered that figures are not always like the shell. I cannot say that I should have known it even from Sow.’s figure, which is much better. Desh. re- gards Phil.’s species as distinct, and (with Dr. Gray) considers this a variety of Ch. gnidia. What changes the creatures make MAZATLAN BIVALVES 73 in other places I do not know, except from the picked speei- mens in Mr. Cuming’s Col. He regards the species as distinct. The Mazatlan shells would never have encouraged any one to unite them: neither Collector nor dealers offered to put them together. Ihave very narrowly examined about 400 specimens of this shell, and more than 600 of Ch. gnidia, nor did I find a single intermediate form. The texture of the shells varies as earthenware from china; Ch. amathusia under the epidermis being glossy, and of avery light brownish purple ; Ch. enidiain the same circumstances having the appearance of a baked shell. dull, and of a darker brown. The concentric ribs are peculiarly lustrous, and are very short and stumpy, rarely shewing any tendency to rise into scales. The radiating strie are very much fainter, shewing a disposition to gather in twos in the young shell. The lunular portion is much larger, smoother, and of aricher purple. Both species within shew the middie teeth slightly furcate, the pallial line distant from the margin. and the sinus small. Ch. amathusia is generally smaller, more swollen, with a thicker shell and margin ; and is more angula- ted posteriorly. It is represented by Ch. cancellata in the Caribbean sea, and its young may be the shell so named in Menke’s Mazatlan list. The smallest specimen found is 1°5 in. long ; the largest measures long. 2°43, lat. 2°74, alt. 1°65. Hab.—? Panama, very rare, C. B. Adams.—S. W. Mexico, P. P. C—Mazatlan; Lieut. Green, (Gould ms.)—Do. ; com- mon and very fine; L’pool & Havre Coll. Tablet 341-contains 3 specimens, rounded form.—342, 8 do. more angulated.—343, 3 do. close ribs.—344, 3 do. produced posteriorly.—345, 3 do. distant ribs.—346, 3 do. swollen form.— 347, 3 do. produced.—348, 3 do. even growth.—349, 1 do. with irregular ribs. In all 25 specimens. 103. Venus (? Co1onz) ————, sp. ind. This can scarcely be the young of Ch. amathusia, since the shape is very different, being subquadrate. Surface more or less distinctly marked with fine concentric ridges and radiating striz, sometimes nearly smooth; lunule clearly marked; an- terior tooth rather long; pallial line distant from margin ; sinus broad, shallow. Colour pink or light green. The largest specimen measures long. ‘09, lat.°12, alt. *06. Oct. 1855. ‘ h 74, MAZATLAN BIVALVES Hab.—Mazatlan ; about a score were found in the dirt frora the small Olive ; L’pool Col. Tablet 350 contains 4 pairs decussated.—351, 1 pair and a See ridges predominant.—352, 2 pairs, nearly smooth. 104 Venus (? CHIONE) pistans, Phil. Venus distans, Phzl. in Zeit. f. Mal. 1851, (Cassel 1852) p. 126. ? Chione distans, Desh. B. M. Cat. Ven. p. 123, no. 13. _ Tablet 353 contains a worn valve, with 2 stout concentric ridges, which comes nearest to this species. Length ‘07. Hab.—Panama, H. B. Philippi? Mazatlan, 1 valve off Spon- dylus ; L’pool Col. 105. Venus (CHIONE) CRENIFERA, Sow. Venus crenifera; Proc. Zool. Soc. 1835, p. 43.—Hanl. Deser. Cat.p.118: Wood Suppl. pl. 16, f. 30.—B. M. Cat. D’ Orb. Moll. p. 67, no. 603.—Sow. Thes. Conch. pt. 14, pl. 156, ih es (AG Chione crenifera, Desh. B. M. Cat. Ven. p. 136, no. 50. ?=V. elevata, Say teste Sow. P=V. radiata, Chemn. t. 36, f. 386, teste Sow. =V. portesiana, D’Orb. Voy. Am. Mer. Moll. p. 556, pl. 83, f. 1, 2, teste Desh. This shell belongs to a group of closely allied Species, one of which is fromthe W. Indies. I am not sure that it is rightly named, but I follow Mr. Reeve’s authority. It fits the original description, as others might, but not the figure or notes in Sow.’s Thes. Conch. The radiating lines scarcely ever group m threes; the shape is suboval, scarcely beaked ; the dorsal area is nearly smooth in one valve, but with the concentric ridges continued over in the other, which overlaps beyond the liga- ment. Surface very irregularly spotted with light chocolate brown. Concentric ridges (which are more or less close) strongly indented and rather glossy. Pallial sinus small, sub- oval.—Anterior tooth prolonged, sharp: cardinal, sub-bifid. Largest specimen (worn) measures Jong. 1°64, lat. 1°87, alt. 1°08. Hab.—St. Elena, in sand at low water; var. Payta (Peru) ; Cuming.—Payta, D’ Orbigny.— Mazatlan: extremely rare ; L’pool Col. MAZATLAN BIVALVES 75 Tablet 354 contains a minute valve, long. °05, and some frag- ments.—355, the most characteristic specimen. 106. Venus (CHIONE) P UNDATELLA, Sow. Venus undatella, Proc. Zool. Soc. 1835, p. 22.—Hanl. Deser. Cat. p.117.—Sow. Thes. Conch. p. 711, pl. 153, f. 22. Chione undatella, Desh. B. M. Cat. Ven. p. 141, no. 68. Tablet 356 contains a broken very young shell which may belong to this species. Concentric ridges numerous; radiating costze just beginning to shew near margin: anterior tooth pro- longed, as usual in young shells. Long. ‘04. Hab.—On the shore, Isle Tres Marias, Gulf of California ; Col. Cuming.—? Mazatlan ; 1 valve, off Spondylus; L’pool Col. 107. Venus (CHIONE) CoLUMBIENSIs, Sow, Venus Columbiensis, Proc. Zool. Soc. 1835, p. 21.—Hanl. Descr. Cat. p. 119: Wood Suppl. pl. 16, f.2.—Sow. Thes. Conch. p. 713, pl. 155, f. 53, 54.—B. WM. Cat. D’Orb. Moil. p. 68, no. 611. Chione Columbiensis, Desh. B. M. Cat. Ven. p. 136, no. 53. Shell remarkably solid, with strong ligament; with deep radiating grooves leaving broad flattened ridges which are crossed by fine concentric ridges, slightly elevated, rising and falling with the furrows, rather irregular, evanescent on the ventral portion, and nearly so on the posterior, where the ribs often rise into scales on the line of the ridges. The shells often show here and there concentric risings of growth, the fresh shell being commenced below the other. In one valve the posterior rib is very large, overlapping the other valve beyond the ligament. Lwunule defined by a deeply cut line, swollen in the middle, and bent at the margin. In these points, and in the character of the hinge, this species closely resembles Ch. verrucosa ; the pallial sinus however is somewhat larger. In more than half the specimens, the prevailing colour is choco- late brown; in the remainder, yellowish white more or less tinged with patches of purplish brown. The young shell is very often white, tipped at the umbos with pink or brownish purple. The smooth ligamental area is always spotted with purple. In the very young shells [?] the concentric ridges are not seen ; afterwards they often go nearly across. Colour inside, white, 76 MAZATLAN BIVALVES often purple, especially on the hinge line. The smallest valve is ‘03 across; the largest measures long. 1°9, lat. 2°, alt. 1°28. Hab.—St. Elena, in coarse sand at low water, Cuming.— Keuador; St. Elena, D’ Orbigny.—S. W. Mexico, P. P. C.— Mazatlan; extremely common; L’pool & Havre Coll. Tablet 357 contains 7 young valves, [?], lunule not defined, very faint concentric lines of growth, anterior tooth elongated, as 1s usual in young Veneride. Tablet 358 contains 7 specimens of the normal chocolate colour.—359, 7 do. with white umbos.—360, 7 do. purplish tinge.—361, 7 do. light coloured, slightly spotted.—362, 7 do. with large patches of dark. 108. Venus (? CoionE) ———,, sp. end. Tablet 363 contains 3 small valves, the smallest only ‘02 across, smooth and white, which do not accord with any of the foregoing species. Hab—Mazatlan ; in shell washings: L’pool Col. Genus TAPES, Megerle. This genus, though the type of a sub-family of Gray, (Bb. MZ. Cat Ven., p. 159) approaches Venus (Chione, Megerle, Gray,) by insensible gradations. The following species may be ranked with either genus. The typical forms have not yet been found in this Zoological province. 109. Tapes HIstRIonica, Brod. & Sow. Venus histrionica Proe. Zool. Soc. 1835, p. 41.—Hanl. Deser. Cat. p. 119;- Wood. Suppl. pl. 16, f. 31—B. M. Cat. D’ Orb. Moll. p. 67, no, 594.—Sow. Thes. Conch. p. 714, pl. 55, £. 52. Chione histrionica, Desh. B. M. Cat. Ven. p. 139, sp. 60. Tapes histrionica, Hanl. Col. suo. This belongs to a group of very closely allied species, of which T. granulata (B. M. Cat. Ven. p. 138,) is the W. Indian analogue, and T. straminea the Californian. It has the form and sculpture of a Tapes, with the teeth and pallial sinus of a Venus. The form varies in the greater or less development of the posterior angle, and in the flattening or rounding of the MAZATLAN BIVALVES 77 ventral margin. The colour is very light brown, more or less spotted or stained with darker in zigzag stripes or blotches. The ligamental area is smooth, and marked off by a decided keel on each side. The keel is almost always painted with spots, even when the rest of the shell is without them. ong. 1°34, lat. 1:58, alt. °8. Hab.—Real Llejos & St. Elena, in muddy sand at low water, Cuming.—Ecuador, St. Elena, D’ Orbigny.— Mazatlan; ex- tremely abundant ; L’pool & Havre Coll. Tablet 364 contains 7 specimens with dark patches of brown. — 365, 7 do. smaller patches.—366, 7 do. very small patches.— 367, 7 do. dark markings obsolete.—368, 7 do. with generaliy diffused shade of lighter brown.—369, 7 do. the same broken up into patches. 110. Taps GRATA, Say. Sow. Thes. Conch. part 13, p. 699, pl. ch., f. 152: (non Desh. in B. M. Cat. Ven. p. 170.) Venus grata, Say Am. Conch. 1830, pl. 26 (teste Jay, 36 teste Sow.) Chione grata, Desh. in B. M. Cat. Ven. p. 140. =(teste Desh.) Venus tricolor, Sow. Proc. Zool. Soc. 1835, p. 41.—Zool. Beech. Voy. p. 151, pl. 41, f. 7—Hanl. Deser. Cat. p.119: Wood Suppl. pl. 16, f.32.—(Tapes t.) Sow. Thes. Conch. p. 699, pl. 151, f. 153. =(teste Jay) Venus discors, Sow. Proc. Zool. Soc. 1835, p. 42.— Hanl. Deser. Cat. p. 118: Wood Suppl. pl. 15, f. 60—B. M. Cat. D’ Orb. Moll. p. 67, no. 600.—C. B. Ad. Pan. Shells, p. 269, no. 436.—(Tapes d.) Sow. Thes. Conch. p. 698, pl. 151, f. 148-150.—(Chione d.) Desh. B. M. Cat. Ven. p. 141, no. 65. ?= Venus Entobapta, Jonas Zeit. f. Mal. 1845, p. 66. ?= Venus neglecta, Phil. Abbild. i. 62, pl. 4. f. 3, (non Gray.) ‘ This shell differs from T. histrionica in not having the smooth ligamental area nor the enclosing carine. The lunule also is less distinct. The large specimen is much more tumid, and more irregularly marked. The hinge teeth are much closer and smaller in proportion, and are very slightly bifid.—Pallial sinus less angulated, smaller. Internal crenations less distinct. An intermediate specimen has one tooth in each valve strongly bifid, and is flattened like T. histrionica. The youngest speci- men scarcely displays bifidity, is much more coarsely and regularly marked, and has the pallial sinus rounder. It is 78 MAZATLAN BIVALVES possibly a distinct species, and closely resembles the W. Indian T. granulata. The largest measures long. 1‘5, Jat. 1°66, alt. 1°06. Hab—W. Coast Mexico, Say.—S. W. Mexico, P. P. C.— Mazatlan, 3 specimens with T. histrionica, Z’yool Col.— (T. discors) St. Elena and Guacomayo, in sandy mud, 6-9 fm., Cuming.—Ecuador, St. Elena, D’ Orbigny.—Panama, Jewett, (Gould ms.)—? Do.: common, C. B. Adams. — Guaymas, Ineut. Green, (Gould ms.).—(T. tricolor) Puerto Portrero, in sandy mud, 11-13 fm. Cuming. Tablet 370 contains the small specimen ; and 371, the largest. 111. TAPES SQUAMOSA, 2. S. T. t. parva, subquadratd, oblonga, alba fusco maculata ; margine dorsali subrecto, postice angulato ; costis fortibus ab umbone prominente radiantibus, liris eoncentricis parte anteriort et ventrali decussatis ; parte posteriori liris obsoletis, costis ibt interruptis, squamosis, maxime costéd ligamento proximad; dentibus 2-3 cardinalibus divergentibus ; sinu pallit subovali ; lunuld impressd. Remarkable for the strong radiating ribs, broken up into scales posteriorly which are very large on the rib next the ligament. On the body of the shell these are decussated with moderately distant raised concentric lines. The young shell has in one valve a long posterior lateral tooth close to the liga- ment. This shell measures long. ‘03, lat. 04; the largest valve long. ‘09, lat. °115, alt. °05. Hab.—Mazatlan; from washings of Chame and Spondyh ; : extremely rare; L’pool Col. Tablet 372 contains the only 3 valves found. Gents ANOMALOCARDIA, Klein. Anomalocardia, Schum. 1817, Essai @une Méth. p. 134.—Desh. B. M. Cat. Ven. p. 115. Triquetra, Blainv. 1818. Cytherea, sp. Lam. Venus sp. Sow. Phil. &e. This small group of Venerida, consisting of species classed sometimes with Venus, sometimes with Cytherea, is well char- acterized by its irregular growth and extremely small pallial sinus. MAZATLAN BIVALVES 79 112, ANOMALOCARDIA suBRUGOSA, Sow. Venus subrugosa, Sow. Gen. f.2.—Rve. Conch. Syst. i. pl. 67, f. 2.—Hanl. Descr. Cat. p.116:— Wood Suppl. pl. 2, f. 6.— Phil. Abbild. Conch. p. 177, pl. 3, f. 6, 7.—Sow. Thes. Conch. p. 721, pl. 155, f. 63.—B. WM. Cat. D’Orb. Moll. p. 67, no. 595.—C. B. Ad. Pan. Shells, p. 271, no. 440. Anomalocardia subrugosa, Desh. B. M. Cat. Ven. p. 116, no. 2. =Cytherea subsulcata, Menke, in Phil. Abbild. (ad fid. spec. ab ipso accept.) This very variable shell is represented on the Atlantic coast by A. flexuosa. It is very coarse and heavy ; generally worn at the umbos. The earlier part of the shell is covered by irregular concentric swellings, which afterwards become eva- nescent on the ventral portion, sometimes all over. These are crossed by rather deeply cut fine radiating lines, which are generally strongest in the depression which marks off the posterior beak, rarely becoming punctato-striate. This depres- sion however often nearly disappears, and the shell approaches A. subimbricata in form. Sometimes it is much flattened, some- times remarkably swollen and gibbous ; sometimes very trans- verse, sometimes much produced ventrally. The radiating grooves sometimes cover the flattened ventral margin, which is very finely crenulated within. The lunule is marked by a well-defined line, and nearly smooth. The teeth and ligament are very strong. Colour generally a yellowish or brownish white,’almost always with 2-4 (generally 3) more or less broad radiating brown stripes ; and the rest often freckled with dots or broken lines. Inside generally with a purple stain about the hinge. Epidermis very thin, very pale or brownish. A transverse specimen measures long. 1°3, Jat. 1°72, alé. °88. An elongated be A BT 7 9 ae mn Bay ho Cae A thick 3 43 Reema 7c lhc BSe Wee Maes Hab.—Panama, Hanley.—Peru, D’ Orbigny.—Panama ; partly buried in coarse sand among stones or under trees, near half tide level, rare; C. B. Adams.—S. W. Mexico, P. P. C— Mazatlan ; in extreme profusion ; L’pool & Havre Coll. Tablet 373 contains 1 minute valve °6 across.—374, 6 young specimens, usual state.—375, 6 do. adult.—376, 6 do. more beaked.—377, 6 do. more swollen, produced ventrally.—378, 2 do. shape of A. subimbricata.—379, 6 do. more transverse.— 380, 3 do. very tumid var. rounded.—381, 6 do. more trans- verse.—382, 4 do. beaked.—383, 5 do. flattened var., produced 80 MAZATLAN BIVALVES ventrally.—384, 6 do. rather beaked.—385, 4 do. more trans- verse.—386, 7 do. transverse form, beak not indented.—887, 6 do. very transverse and indented.—Groups shewing colour. Tablet 388 contains 2 sp. whitish var. normal.—389, 2 do. trans- verse.—390, 2 do. flat.—391, 2 do. tumid.—392, 3 sp. yellowish var. normal.—393, 3 do. transverse.—394, 2 do. rounded.—395, 1 do. tumid.—396, 3 do. orange var.—397, 3 sp. dark var. nor- mal.—398, 3 do. elongated.—399, 3 do. rounded.—400, 3 do. tumid.—401, 3 do. form of A. subimbricata.—402, 3 sp. broad bands.—403, 3 do. speckled.—404, 3 do. narrow bands.—405, 2 do. and a valve, bands very faint. Tablet 406 contains 3 sp. strongly rugose.—407, 3 do. smooth form.—408, 3 do. shewing the inside.—In all 130 specimens. 113. ANOMALOCARDIA SUBIMBRICATA, Sow. Venus subimbricata, Proc. Zool. Soc. 1835, p. 21.— Wood Suppl. App. pl. 15, f. 57.—Sow. Thes. Conch. p. 711, pl. 154, f. 35-38. Anomalocardia subimbricata, Desh. B. M. Cat. Ven. p. 117, no. 4. Only a very few small pairs and some young dead valves were found of this species, which further south is not uncom- mon. These few however exhibited remarkable differences. Sometimes the form was regular, sometimes extremely gibbous. Sometimes the concentric folds were rounded; sometimes as though the shell was raised at intervals and a fresh shell begun below; sometimes the radiating ribs were crossed by angular lamine, as in Ch. amathusia and gnidia. © In this state it may possibly be the V. cancellata of Menke’s Maz- atlan catalogue (Zeit. f. Mal. 1847, p. 191); unless indeed that be a young specimen of one of the species above named, from which it may be told by the extremely minute pallial sinus. Very rarely the concentric ridges scarcely appear in the young shell, in which state it might easily be taken for another species. In one very young specimen, on the other hand, the concentric folds are sharp, while the radiating ribs are nearly evanescent. The largest specimen only measures long. 1°04, lat.1°1, alt. °77. Hab.—Puerto Portrero, in fine sand, 13 fm. Cwming.—Acapul- co, Sowerby.—S. W. Mexico, not uncommon, P. P. C.— Mazatlan ; extremely rare; L’pool Col. Tablet 409 contains 2 minute valves.—410, 5 valves of various forms.—411, the gibbous specimen. MAZATLAN BIVALVES 81 Fimity ASTARTID ZA, Cyprinide, Forbes, Woodw. This name has been previously appropriated for a family of Fishes. Gray divides it into four families, Carditide, Astartide, Crassatellide, and Glos- sidee{(Isocardia, Lam.) Genus CIRCE, Schum. Cytherea (pars) Lam.—This genus is ranked with the Veneride by Gray & Desh., with Astarte and Cyprina by Forbes and Woodw. 114. CIRCE MARGARITA, 7. s. C. t. minima, subovali, inequilaterali, umbonibus appressis, subrugosis, concentrice liratéd, liris acutis, ared lunuldque indistinctis, ligamento celato: parte antertori dilata, posteriort parva; dente laterali antico maximo, alterd in valva in cardinalem confluente ; postico longo, exili: cardinali- bus 2-3: impressionibus muscularibus, subaqualibus, lined pallia ad margine remota ; albd flavescente, dentibus purpureis ; epti- dermide tenut. This genus abounds in the Red Sea, Australia and the East Indies generally. It has not been described from the American coast. I have several species in a collection sent from the U.S. as from S. America; but as nearly all are identical with Aus- tralian species, the locality is probably erroneous. The charm- ing little C. margarita however establishes its claim to a place in the genus, by its appressed, somewhat rugose umbos, semi- internal ligament, large anterior tooth, and the pallial line which, though generally indistinct, is certainly not sinuated. It is oval, with very delicate, rather sharp concentric lines, covered with a thin epidermis ; sometimes subdiaphanous, sometimes opaque and yellowish inside, with a purple tinge on the teeth. It may be the young of a larger species not yet discovered, but as about a score of specimens were found fresh, nearly of the same size, and with the rugose portion of the umbos clearly distinguished, it may not improbably be adult. Long. ‘05, lat. °07, alé. °03. Hab.—Mazatlan ; on Spondylus Lamarckii, very rare; LZ’ pool Col. - Tablet 412 contains 1 pair closed; 2 do. open, (the largest and smallest,) and 1 yellowish valve. 82 MAZATLAN BIVALVES 115. P CIRCE SUBTRIGONA, 2. s. C. t. parva, subtrigond, postice longius, margine ventrali ovali; concentrice tenuissime striatds; wmbonibus ap- pressis, subrugosis ; ligamento celato ; dentibus lateralibus posticis magnis, anticis subapproximatis ; impressionbus muscularibus 4 margine distantibus ; albo-lutescente, macula uscd postice, intus subrugosé, et linets divaricatis huc et alluc pictd ; epidermide tenut. Known at once from C. margarita by its shape which is longest behind ; by the very fine concentric strie; the large posterior tooth (not so large however proportionally as the anterior tooth of C. margarita;) and the painting, which dis- plays a large irregular brown patch inside, which projects somewhat above the regular level and is slightly rugose, and a few irregular zigzag lines on a yellowish white ground. I have not been able to trace the pallial line. There is no trace of sinus, though the colour markings sometimes give an erroneous appearance of it. In other respects the generic characters are satisfactorily marked. It is somewhat less uncommon than C. margarita, though I found very few fresh specimens. This greatly exceeds it in size. Long. °08, dat.‘ 11, alt. °04. Hab.—Mazatlan ; on Spondylus Lamarckii, rare; L’pool Col. Tablet 413 contains 2 minute valves, cardinal teeth not formed; 2 adolescent and a pair united; and 2 valves adult. Genus GOULDIA, C. B. Adams. As I have neither had the good fortune to find the original diagnosis of this genus, nor to meet with any conchologist who understood it, 1 can only guess what it was meant to include. The late learned and very accurate Prof. Adams, in his descrip- tion of the following species, gives no account of the teeth. Fortunately however Mr. Cuming possesses and has allowed me to examine type specimens of G. parva and Pacifica, received from the Professor. The former bears a general resemblance to our ? Circe minima: the second is undoubtedly the Mazatlan shell, and is like an Astarte with lateral teeth, such as occur in not a few of the Crag species. A third species is now added, from its general agreement with the second. MAZATLAN BIVALVES 83 116. Goutpra Pactrica, C. B. Ad. ©. B. Ad. Pan. Shells, p. 275, no. 450, The only pair found (and that imperfect) was unfortunately smashed just after it had been sketched. 1t was of a rich lus- trous brown like Petricola robusta. The shell has all shades toadingy white. About 18 odd valves were found, by no means constant in their characters. The general appearance is remarkably like a little fossil Astarte noticed in a communi- cation made to the British Association, L’pool, 1854, (v. Re- port, p. 78,) flat, triangular (in that respect alone like Tellina Burneti) and with very distant ribs outside. These ribs are generally sharp, but sometimes rather flat and rounded. The anterior dorsal margin is concave in young specimens. The surface of the shell appears under the glass, covered with fine radiating stris; but under the microscope these lines are found to be simply the divisions between rows of parallel ‘oblong dots, which most resemble the strung figs of commerce, and are laid in rows, side by side, over the surface of the shell. These show. through in very young specimens, and present a most beautiful appearance. Inside, one valve has a long anterior lateral tooth, a short distant posterior one, and 3 nar- row divergent cardinal teeth, of which the middle one lies between two broad pits, and the anterior joins on to the lateral. The other valve displays along posterior, and small distant | anterior lateral ; with 3 cardinals, of which one is the beginning of the posterior lateral, the middle rises between two pits, and the anterior is marginal, nearly obsolete. Muscular and pallial marks distant from margin. The largest valve measures long. °16, lat. °18, alé. °05. Hab.—Panama; not common; C. B. Adams.—Mazatlan ; off Chame and Spondylus, very rare ; L’pool Col. Tablet 414 contains 4 valves, of different ages, and a fresh fragment to shew the ‘strung-fig’ structure. 117. GouLDIA VARIANS, 2. s. G. t. minima, subtrigond, subequilaterali, formd plus minusve angulato-rotundata, plus minusve elongata ; albidd, plus minusve fusco maculaté ; sublevi, striis incrementi, sive costis concen- tricis paucis seu nwnerosis ; superficie lineis granulosis radi- antibus creberrimis celaté ; umbonibus subspiralibus, haud conspicuis ; margine sumplici, appresso; dentibus lateralibus 84, MAZATLAN BIVALVES altera valvé postico, altert antico magnis, iongis ; cardinalibus 3-3, quarum medius altera valva minimus, alteré maximus ; im- pressionibus muscularibus subrotundatis, lined pallii a margine distantiore. Four or five well characterized species might easily be de- scribed from extreme forms of this variable little shell. Like one of the Crag fossil Astartidx, it has concentric ribs either near the umbo, all over the shell, or not at all. Sometimes in forming lines of growth, it leaves a sharp projecting ridge. Sometimes it is of a somewhat regular Venus shape (especially when young); sometimes it is narrowed and unusually pro- longed. Even in its most ribbed form, it differs from G. pacifica in being very much smaller, not so fiat, with umbos more spirally projecting, and with the anterior dorsal margin less coneave, as well as in having the ribs smaller, and closer. it has the general size and appearance of Astarte triangularis. The colour is generally whitish, with a large anterior brown stain. The teeth are on the plan of G. pacifica, but display specific differences in their comparative size. The surface under a high power displays the strung-fig pattern, but on a very much finer seale than in G. pacifica. Underneath the outer layer, the shell is somewhat granulose. About a score of pairs and more than 200 single valves were found on the large shells. it was not noticed by C. B. Adams at Panama, but it probably finds its way as far South, as I found it on specimens of Murex regius said to come from that place. The smallest specimen measures Jong. ‘03, lat. "035, alé. *015. The largest 29 29 39 “09, See O08, 33 “05. Hab.—Mazatlan ; common in shell washings; L’pool Col. Tablet 415 contains 1 pair and 12 valves ribbed.—416, 4 valves ribbed near the umbos.—417, 6 valves, nearly smooth.—418, 5 valves regularly rounded.—419, 5 valves elongated. Gents CARDITA, Brug. 118. Carpita Catirornica, Desh. Proce. Zool. Soc. 1852, p. 100. ?=Cardita affinis, Menke in Zeit. f. Mal. 1847, p. 188; et Gould ms.: non Sow. As this is the northern form representing the more tropical C. affinis (Sow. Proc. Zool. Soc. 1832, p. 195; v. also C. B. Ad. Pan. Shells, p. 264) it is probably the shell quoted as C. affinis MAZATLAN BIVALVES 85 by Menke in his list of Melchers’ Mazatlan shells, and by Gould as collected by Lieut. Green at Guaymas. I have C. affinis from S. W. Mexico; but all, even the most minute, specimens from the Mazatlan collection belong to this species. C. Californica differs from C. affinis (as far as my few speci- mens enable me to judge) in being rather less transverse, less incurved at the anterior ventral part, less narrow and projecting anteriorly, with the ribs rounder, larger, and covered with very large scaly protuberances at the posterior end. The colour also is much redder, and the epidermis lies m much finer concentric lines. C. Californica begins life in an irregular way without ribs, as a tiny white creature with concentric strie. The ribs how- ever On appearing soon become very large and well armed. The creature then looks like a tiny Tridacna, with extremely projecting umbos, subtrigonal, and nearly equilateral. At this time there is alarge, distant, anterior lateral tooth. (There seems a general tendency among bivalves, in their earliest stage, to an abnormal development of the anterior portion. PIs the foot then more active than the siphons. Gradually the posterior part grows, the colour appears, and the anterior tooth draws nearer (proportionally) to the hinge. There are generally one or two fewer ribs developed in the young than in the adult. The smallest specimen is ‘03 across; the largest measures long. ‘78, lat. 1°38, alt. °5. Hab.—Gulf of California, Mus. Cuming.— Mazatlan ; extremely rare adult, rare jun., nestling in crevices of Chamez, Spondyh, Ostree and Perna; L’pool Col.—?Guaymas, Lieut. Green. Tablet 420 contains 3 minute valves and 2 pairs jun.—421, a young specimen in situ on the back of a Perna, on which is the lower valve of Discina Cumingii, attached.—422, an adult specimen. Gents VENERICARDIA, Lam. 119. ? VenERICARDIA ————,, sp. ind. Tablet 423 contains a minute valve, whose characters are all those of Cardium except the hinge. This however presents a triangular cardinal tooth, with pits for the 2 opposite ones, and an indistinct, closely approximate anterior lateral. There is no trace of posterior tooth. The outside is ribbed almost exactly as in Cardium graniferum; but instead of the inter- Nov. 1855. a 86 MAZATLAN BIVALVES stices being pitted, the whole shell is decussated by very fine rather distant concentric ridges, passing over and between the ribs. The large ventral ribs are hollowed in the interior of the shell. Long. 03, lat. °04, alt. *02. Hab.—Mazatlan ; one valve in Spondylus washings; L’pool Col. Genus P TRAPEZIUM, Megerle. Megerle von Mihi feld, Entwurf &e. p. 68, 1811 :—Phil. Hand. Conch. p. 350. Libitina, Schum. 1817. Cypricardia, Lam. An. s. Vert. 1819. 120. ? TRapEzIUM ——— , sp. ind. Tablet 424 contains a puzzling little shell, too young to identify even generically. It is shaped like the adult, not the young of Cardita, but entirely without radiating ribs. Shell transparent, subrhombie, irregular, anteriorly truneate, umbos projecting, lateral; valves smooth, with a few regular distant — concentric epidermal ridges ; inside with avery stout projecting cardinal tooth, fitting between two small ones in the opposite valve, and a posterior lateral tooth in each. Ligament external : no trace of pallial sinus. Long. ‘02, lat. 04, alt. °03. Hab.—Mazatlan ; 1 pair, in shell washings ; L’pool Col.* Famity CHAMID. This aberrant family is placed by Lam. and Woodw. between Unio and Tridaena ; by D’Orb. between Spondylus and Ostrea ; by Gray between Saxicava and Cardita; by Phil. between Cardium and Lucina. In its adherent mode of life and irregular growth it resembles Ostrea ; while its two large adductors and its siphons remove it far away. Both animal and shell have relations with Isocardia (Glosside, Gray) which was, not so unnaturally as might appear at first sight, associated with it by Linneus. * Of the two species of Gouldia in the Cumingian Collection, G. cerina, C. B. Ad. is congeneric with the so called ‘ Circe’ minima, not with the G. Pacifica of the same author. Congeneric with the latter species and with G. varians are Crassatella Martinicensis, D’Orb., intermediate in form between the two. Mazat- lan species, and Crassatella Guadaloupensis, D’Orb. the exact analogue of G. Pacifica. For which group the generic name is to be retained, those who have seen the diagnosis must decide. MAZATLAN BIVALVES 87 Genus CHAMA, (Pliny,) Linn. 121. CHama FRONDOSA, Brod. var. MEXICANA. Chama frondosa, var. b. Brod. Proc. Zool. Soc. 1834, p. 149.— Zool. Soc. Trans. vol. i. p. 302, pl. 38, f. 1,2.—Rve. Conch. Ie. pl. 1, f.16.—B. M. Cat. D’ Orb. Moll. p. 87. no. 773. Compare Chama echinata, Brod. in Zool. Beech. Voy. p. 150, pl. 48. f. 9—(P=C. echinata, pars, Brod. Proc. Zool. Soc. 1834, p. 150 :— Trans. Zool. Soc. 1835, p. 305, pl. 39, f. 57.— Rve. Conch. Ic. pi. 7, f. 35, jun.—C. B. Ad. Pan. Shells. p. 254, no. 407.) The Mazatian Chame were sent in tolerable numbers, and yet so commonly were their surfaces abraded that it is difficult to discriminate the specific characters. The bulk of them are certainly C. frondosa, var. b, of Brod. and Rve., but were con- sidered a distinct species by Messrs. Cuming and Hanley. The typical C. frondosa comes as far north as S. W. Mexico (P. P. C.) but was not found among the Mazatlan shells. I have not ventured however to describe it as a distinct species, till more is known of its power of local variation. Shell when extremely young (as shewn by examining the umbos of the smallest valves found, under a half-inch achrom.) somewhat Venus-shaped, with concentric ridges, and a very finely shagreened surface, occasionally passing into very fine radiating strie: interior as in adult. Many of the shells do not display this structure, but pass at once to the next stage, generally with vaulted spines, sometimes with irregular lamine. The inner margin at an early state is not crenulated: colour white, gradually developing a rich pink. In its adolescent condition, the interior is of a rich plum purple, irregularly diffused, more or less stained with orange, especially at the teeth. The margin during this period often displays a most minute set of crenulations, within the line of meeting of the valves. All the specimens found in this state had lost their external characters. When properly adult, it is generally cover- ed with very irregular concentric layers rising into lamelle, rarely into spines, with a tendency to broader foliation in a pos- terior radiating area, ill defined. The interior crenations become then almost extinct. Colour outside brownish red, within white, more or less stained with the same. Shell attached sideways, generally by about a third of its surface, with very large adductors, and hinge teeth which are more or less ser- rated; white, bordered with purplish brown. The ligament 8s MAZATLAN BIVALVES is strong, curling round the umbos, like Isocardia, and becom- ing semi-internal beyond the hinge teeth. All the specimens are dextral. The lamine are generally finely striated outside. These shells, like those of Spondylus, offered a safe retreat for boring and nestling bivalves and numerous minute Gas- teropods. The smallest valve measures ‘02 across. That with the largest animal, (shell somewhat thin,) long. 4°5, lat. 4°25. alt. 3'4. The heaviest shell measures externally {though part has been removed) long. 5°7, lat. 5°, alt. 5°; internally (from ligament to margin) long. 2°6, lat. 2°8, alt.2°2. This, with another smaller specimen attached, weighs 5lb. ; and displays a very large and persistent spiral ligamental groove. Hab.—Guif of Tehuantepec, Mexico; dredged up from sandy mud attached to Avicule, 10 fm. ; Mus. Cuming.—Mazatlan ; not cominon; L’pool & Havre Coll.* Tablet 425 contains 3 valves, extremely young, exhibiting the shagreened surface at the umbos.—426, 2 do. umbos finely striated.—427, 1 do. umbo spiral, as in young Calyptreade.— 428, 1 do. concentric foliations developed. — 429, 8 valves, a stage older, spiny processes developed, valves inside variously coloured, and surface rugose.—430, 1 pair and 3 valves, a stage older, colour highly developed. Tablet 431 contains 1 pair young.—432, a specimen with the spiral umbos so enormously developed, as to approach the fos- sil form Diceras. The umbo of the attached valve makes two loosely spiral whirls, the hgament running up the suture; in length it nearly equals the breadth of the shell, but being filled up with solid matter, would not display itself in the internal cast. Tablet 433 contains a pair, young, purple and orange, (closely resembling the C. echinata, “‘very old,” figured in Beechey’s Voyage.) Margin very finely, and teeth strongly crenate. Outside, with Vermetide, Lithophagi, &e.—434, 2 valves at- tached to each other, pierced by Lithophagi, &c. The outer layer has become eroded, except where the Lithophagi have bored. Tablet 435 contains a diseased specimen, purple, attacked by Lithophagi, even to the very centre of the teeth. Tablet 436 contains a finely grown adult specimen, attached to Pinna, with Vermetide &c.—437, the sp. with the largest animal.—438, the group with the largest shells. * A specimen received from Dr. Gould of this species (without reference) is probably the ‘OC. Pacifica” of his list, ‘‘Guaymas, Lieut. Green.” It may however be the C, Buddiana, C. B. Ad.; v. infra. MAZATLAN BIVALVES 89 121, 6. CHAMA P FRONDOSA: va7’. FORNICATA. C. ?frondosa, t. costis numerosis irregularibus radiantibus, squamis fornicatis crebris indutis ; huc et illuc frondosd ; intus alba, ad marginem rubro-purpured ; margine crenulato ; den- tibus ad apicem valde serratis ; epidermide cinerea ; per totum latus affixd. Compare C. Buddiana, C. B. Ad. Pan. Shells, p. 253, no. 405 ; Panama, rare ; Guaymas, Lieut. Green. A few specimens differed from the rest of the Mazatlan Chame in having the surface (especially anteriorly) covered with radiating coste, rising into scales which are often semi- tubular. The colour never displays the rich purple and orange of C. frond. Mexicana, being white bordered with puce. The attachment is more completely lateral ; margins more strongly crenate; edge of hinge tooth sharply serrate. Shell covered with an ashy epidermis, sometimes olivaceous, not noticed even in young specimens of C. frond. Mexicana. These charac- ters might be sufficient to mark out a species, if constant: but as I find many of the adult specimens that cannot be referred - with certainty to either form; and as each of the characters (except that of the epidermis) is in both forms subject. to vari- ation, their claim cannot be regarded as established. The shell seems to have relations both with C. Broderipu and C. Buddiana: on the other hand it sometimes displays posteriorly more of the characters of C. frondosa proper than does the ordinary form. The valves unite so closely that a specimen (attached to Byssoarca) on being opened, two years after being brought to this country, was found full of the soft animal mat- ter, of course in a state of the most fetid decomposition. In the young state it is not to be distinguished from C. frond. Mexicana, and scarcely from C. spinosa. It is also of the same size and habit of growth. Hab.— Mazatlan ; very rare; L’pool Col. Tablet 439 contains 2 pairs and a valve, very young.—440, a pair young.—441 a pair well formed, adhering to the inside of a very large valve. The latter is incrusted with Sponge, Ver- metide, &c., and nestled beneath the umbo two specimens of Byssoareca gradata have found a home. 442, a sp. attached to living Byssoarca ipacifica (v. supra).—443, a large specimen, containing i in the upper valve Petricola robusta.) in situ; in the lower, which had been attached to ? rock by a large surface, 90 MAZATLAN BIVALVES a Gastrochena truncata in its burrow, and a Petricola robusta which, after penetrating to the ?rock, has flattened itself rather than bore into the harder substance. 122. CHama spinosa, Brod. Proc. Zool. Soc. 1834, p. 150.—Rve. Conch. Icon. in loc. Three small valves and one pair appear to belong to this species. The valves differ from the young of C. frond. fornicata, in having the entire surface crowded with semi-tubular spines ; and in the character of the margin, which is smooth and rounded within, outside with crowded scales one on another, like the base of Hipponyx tessellata. The types and the pair do not display this structure, which appears very characteristic. Hinge teeth comparatively small; muscular scars not very large ; colour white, with slight rosy tint at the umbos which are scarcely spiral. Long.1°1, lat.1°1, alé. °08. Hab.—Lord Hood’s Island, Cuming.—? Mazatlan; extremely rare; L’pool Col. Tablet 444 contains avalve. The pair will be seen, attached to Ostrea, with Discina, on tablet 20. 123. Coama PExoGcyrRa, Conr. One broken pair attached to a pebble, and a valve on Spondy- lus ealeifer in the Liverpool Museum, differ from the rest of the Mazatlan Chame in the following particulars. Shell sinis- tral; ventrally produced; surface roughened and laminated, not spinous; margin smooth, rounded off, slightly crenate outside; teeth long, small, colour reddish brown, without purple. They may belong to Ch. Panamensis, or even to Ch. corrugata, but seem best to accord with this species. Long. 1°5, lat. V7, alt: 1°15. Hab.—Sta. Barbara, San Diego, &c. Nuttall—Mazatlan ; ex- tremely rare ; L’pool Col. \ Tablet 445 contains the specimen on pebble. Famity CARDIAD. Genus CARDIUM, Lunn. Only two species of this abundant genus were sent in any quantity ; the shell washings however proved that many more must exist in the neighbourhood ; 5 species being found suf- MAZATLAN BIVALVES 91 ficiently perfect to describe with tolerable accuracy; and fragments of 5 others presenting characters by which they may be hereafter distinguished. 124. Carpium (L&VICARDIUM) ELATUM, Sow. Pyro. Zool. Soc. 1833, p. 84.—Rve. Conch. Ic. sp. 41, pl. 8, f. 41. This most magnificent cockle is known at once by its large size, smooth surface and yellow colour. It has however very faint, nearly obsolete ribs, covering the body of the shell ; but even these are not to be seen ona large, distinctly marked, posterior and a smaller anterior portion. About the umbos there are no longitudinal ribs, but very faint concentric ridges of growth. The shell has a decided posterior gape: edges crenated within, except at the smooth parts: posterior lateral tooth in one valve marginal. Epidermis thin, crossed with numerous very fine concentric ridges. IfI have rightly affiliated the young shells, (but there is nothing intermediate between ‘11 and 2°63,) in its early state it is somewhat spotted, and much more transverse. The little shells suit better the description of C. Elenense. The teeth vary greatly in size, and the shells in thickness. Some of the young shells under a low power, and all under a high one, dis- play a pustulose surface, which Pmay be traced near the umbos of the smallest distinct specimen of C. elatum. The smallest minute valve is ‘03 across; the largest specimen measures long. 5°85, lat. 4°58, alt. 3°92. Hab.—Guaymas, in sandy mud at low water, Mus. Cuming.— San Diego, Lieut. Green.—Mazatlan ; not uncommon ; L’pool &§ Havre Col. Tablet 446 contains the smallest and largest distinct speci- mens.—447, 3 perfect and 2 imperfect valves of C.? elatum, jun. 125. CaRDIUM PROCERUM, Sow. Proc. Zool. Soc. 1833, p. 838.—Mill. Syn. Test. Viv. p. 216.— Sow. Conch. Ill. no. 61, pl. 50, f. 23.—Rve. Conch. Syst. pl. 77, f. 23 :—Conch. Ic. pl. 10, £ 51.—Hanl. Deser. Cat. p. 140.— Menke, Zeit. f. Mal. 1847, p. 188, no. 51.—_B. M. Cat. D’ Orb. Moll. p. 74, no. 659.—C. B. Ad. Pan. Shells, p. 267, no. 433. This shell deserves favourable regard not only on account of the beauty of its form, but also because it has been quoted in 92 MAZATLAN BIVALVES no fewer than eleven books without asynonym! The young shell however has not been so well treated, being, according to Jay and Reeve, the C. laticostatum of Sow. It certainly suits exactly the description and measurements given in Proce. Zool. Soc. 1833, p. 85. Mr. Cuming however states that C. laticostatum is distinct and is the larger of the two! The young C. procerum moreover is not to be distinguished from the figure of the young C. Panamense in Zool. Beech. Voy. pl. 42, f. 7, which is described by Sow. Proc. Zool. Soc. 1833, p- 85, as only 1°5 in. long. The specimens in the Cumingian Collection however are extremely large. The Mazatlan shells are manifestly of one species. It begins life nearly orbicular. A young shell, ‘5in. long, displays 7 close posterior ribs, sharply serrated at the margin, and with rows of tubercles on their summits. The 10 ventral ribs are then subtriangular, rather sharp, minutely dotted at the top, and with the sides and very narrow interstitial spaces finely decussated by con- centric ridges which travel up and down over them. The six anterior ribs are very much flattened, and faintly decus- sated by the concentric lines—Gradually both tubercles and concentric ridges disappear, at an earlier or later period; the ribs then become flattened, and at last on the anterior part nearly pass away. The shell assumes a longer or broader form, with every gradation between. The number of ribs varies from 21—25, and does not depend on the shape. The colour is whitish, variously spotted with reddish brown; inside near the posterior margin, (which is very ringent,) of a rich brown- ish purple. The ends of the ribs project beyond the margin of the shell at the posterior ventral part, and beautifully inter- lock. The side teeth are in a very slight curve from the car- dinal. Epidermis thin, with very closely concentric ridges. A broad specimen measures long. 2°5, lat.2°2, alt. 2°04. The largest ,, i BOM ek es Ost eer Hab.—Real Llejos, in coarse sand 4-6 fm. Cuming.—Payta, D Orbigny.—Panama, rare, C. B. Adams.—S. W. Mexico, P. P. C.—Mazatlan, Melchers.— Mazatlan: common ; P’pool & Havre Coll. Tablet 448 contains a minute imperfect: valve.—449, broad variety, 5 pairs and a valve, young.—450, do. 3 sp. adult.— 451, 4 sp. young, elongated form.—452, 3 do. adult.—453, a curiously deformed valve. i MAZATLAN BIVALVES 93 126. Carpium ?PsENntTIcosuM, Sow. Proc. Zool. Soc. 1833, p. 84.—Mill. Syn. Test. Viv. p. 218.— Sow. Conch. Ill. no. 43, pl. 47, f. 10—Rve. Conch. Syst. pl. 74, f. 10:—Conch. Ic. Ind. Card. & Errata.—Hanl. Deser. Cat. p. 137.—B. M. Cat. D’ Orb. Moll. p.'74, no. 658.—C. B. Ad. Pan. Shells, p. 268, no. 434. =Cardium rastrum, Rve. Conch. Ic. pl. 16, f. 82.* P=Cardium muricatum, Menke in Zeit. f. Mal. 1847, p. 188, no. 50. Tablet 454 contains a nearly perfect minute valve and 6 frag- ments of larger shells, which probably belong to this species. The ribs are extremely close, about 40, and bearing traces of grains which are strongest on the anterior side. The smallest fragment has a fine line running down the interstices, which is probably an accidental variety, as I have a specimen of C. echinatum displaying the same structure. C. muricatum is the West Indian analogue. Hab.—St. Elena, in sandy mud, 6-12 fm. Cuming.—Ecuador ; St. Elena, D’ Orbigny.—Taboga; very rare; C. B. Adams, — ? Mazatlan; extremely rare, in shell washings ; L’pool Col. 127. CaRDIUM — sp. ind. (a.) C.t. 2jun. minima, orbiculari, costis circiter xl. approxima- tis, haud extantibus, graniferis; superficie totd minutis- sime quasi arenatd, dentibus lateralibus haud magnis. Two valves anda fragment only were found of this shell, differing from C. punctulatum, Brod. & Sow., Zool. Journ. vol. iv. p. 366, in the characters above named. The entire surface appears as though dusted over with grains of sand. It appears to be a young shell: if the adult, when found, have the same characters, it may take the name of C. arenatum. Long. 08, lat. 08, alt. “06, Hab.—Mazatlan ; from Spondylus washings ; extremely rare ; ‘pool Col. Tablet 455 contains a nearly perfect valve. - * “Mr. Reeve’s reference to P. Z. S. 1841 for Sowerby’s description is evidently a misprint for 1833; and the reference to the same work, 1845, for C. rastrum seems erroneous. Mr. Hanley’s reference to Reeve Conch, Syst. pl. 84 is also q misprint for 74.” (C. B, Adams, loe. cit, 94, MAZATLAN BIVALVES 128. CarpIumM ————-, sp. ind. (b.) Tablet 456 contains a fragment of a shell of moderate size, which may possibly be C. triangulatum, Sow. (St. Elena and Isle Plata, Cuming.) It has very broad flat ribs, with 2 rows of tubercles on each. These communicate with decussating lines in the interstices. Hab.—Mazatlan ; from shell washings ; L’pool Col. 129. Carpi1um ———— sp. ind. (ce.) Tablet 457 contains a fragment of a moderate sized Cardium, having relationship with C. pseudofossile, Rve. (Behring’s Str.) It is of a dead white, with very close, stout, numerous, rounded ribs, barely nodulous. Hab.—Mazatlan ; from shell washings; L’pool Col. 130. CarpIuM —— sp. ind. (d.) Tablet 458 contains a fragment of a thin white shell with perfectly triangular, rather distant ribs, with flat sides. The interstices are smooth, bounded by clearly marked lines. Hab.—Mazatlan: from shell washings; L’pool. Col. 131. Carpium ————., sp. ind. (e.) Tablet 459 contains 2 fragments, something like the last, but coloured, and with the ribs rounded and slightly nodulous. Hab.—Mazatlan ; from shell washings ; L’pool Col. 132. Carpilum ———— sp. ind. (f.) Tablet 460 contains 2 minute fragments, with very narrow smooth rounded ribs, very far apart. Interstices broad, smooth, bounded by distinct lines. Hab.—Mazatlan ; from shell washings ; L’pool Col. 133. CARDIUM ALABASTRUM, %. s. C. t. parva, alba, nitidd, subdiaphand, subequilaterali, elongata ; costis circiter xvill., quarum quatuor ventrales magne, distantes, costellis utrdque subtrigonu- latis apicem versus granulatis ; interstituiis minutissime decus- MAZATLAN BIVALVES 95 satis; parte anteriore punctis ovalibus wmpressis decussaté ; dentibus lateralibus approximatis. ‘This charming little creature has a general resemblance told a minute C. costatum; but the large ventral coste are rather rounded, with a little one on each side making them appear somewhat trigonal. The anterior portion is strongly indented with oval pits. The appearances it presents under the micros- cope vary greatly according to the direction of the light. The young shells have fewer ribs near the hinge, where the teeth are not fully developed; are rather less equilateral; and are granulose on the ribs. Long. ‘12, lat. *11, alt. °08. Hab.—Mazatlan; in Chama and Spondylus washings; ex- tremely rare. Tablet 461 contains 2 valves, the largest and the smallest. 134. CARDIUM GRANIFERUM, Brod. 5 Sow. Zool. Journ. vol. iv. p. 367.—Sow. Conch. Ill. no. 38, pl. 49, f. 17.—Rve. Conch. Syst. pl. 76, f. 17 :—Conch. Ic. pl. 8, 43.— Hanl. Descr. Cat. p.137.—C. B. Ad. Pan. Shells, p. 266, no. 430.—B. WM. Cat. D’ Orb. Moll. p. 73, no. 652. The smallest valve found, which only measures ‘03 across, scarcely shews a trace of teeth. The young shells are nearly rectangular at the posterior end ; when older, they are obtuse angled. The interstices between the ribs are decussated by a series of rectangular impressed pits laid transversely. The largest specimen found measures only long. ‘12, lat. *12, alt. °06. Hab.—Dug from a depth of about 6 inches in the mud of the Estaro de Mazatlan; Lieut. Belcher.—Gulf of Nicoyia and Xipixapi; Cuming, D’ Orbigny.—Panama, extremely rare, C. B. Adams.—Mazatlan ; a very few young valves and frag- ments in the washings of Chame and Spondyli; Z’pool Col. Tablet 462 contains the largest (imperfect) valve, and two small ones. 135. PCarpIum ————, sp. ind. (g.) 2C. t. guniore suborbiculari, albidd, valde inequilaterali ; margine dorsali postice recto, antice concavo ; costis circiter xviii. validis, rotundatis, approximatis, tuberculis latis armatis ; dentibus elongatis, lateralibus distantibus. 96 MAZATLAN BIVALVES A puzzling little shell, of which were found only one minute valve and a larger fragment. Remarkable for the very stout ribs, well armed with coarse tubercles, and for the Lucina-like shape of the dorsal margin. It has about 10 ventral ribs, but the species probably has more when adult. If then of the same shape, it may take the name of C. lucinoides. Long. ‘04, lat. ‘04, alt. °03. Hab.—Mazatlan; extremely rare; in shell washings; L’pool Col. Tablet 463 contains the valve. Famity LUCINIDA. ~ Genus LUCINA, Brug. This genus, so abundant in the Atlantic, and especially in the West Indies, appears very rare on the Pacific coast of America. C.B. Adams records only one species from Panama, and this does not belong to the genus; D’Orbigny none from the West coast of S. America. Reeve describes 3 species (fibula, eburnea, and calculus) discovered by Mr. Cuming, be- sides L. punctata and muricata, previously known; and L. annulata from ? California. Dr. Gould has another, from Acapuleo. Only one small species was at all common in the Mazatlan collection ; though there is evidence of the existence of a tolerable number of others. Some of the Lucine are not at all constant in their characters ; the same species sometimes displaying, or not, radiating and concentric ribs, and having its margins smooth or crenated. Not a few of the species appear to have a very wide distribution; L. occidentalis, Rve. (olim pecten) being quoted from the West Indies and Ld. Hood’s Island, and L. borealis from the British Seas and the Philippines. Many of the Mazatlan species were found en- tangled in the byssal mass of the large Modiole. 136. Lucina (CopAKIA) TIGERINA, Lin. Venus tigerina, Zinn. Syst. Nat. p. 1133-4.—Born Mus. p.70.— Chemn. vii. p. 6, t. 37, £. 390-1.—Schroeter Hinl. iii. p. 136.— Mont. Test: Br. p. 119, t. 4, £.1—Dorset Cat. p. 35, t. 1. f. 14.—Dillw. Cat. vol. i. p. 191, no. 76 :—&e. Cytherea tigerina, Lam. An. s. Vert. ed. 2, vol. 6, p. 318.— Turt. Dyth. Br. p. 164, pl. 10, f.12.—Flem. Br. An. p. 445. MAZATLAN BIVALVES 97 Lucina tigerina, Desh. Enc. Méth. vers. t. 2, p. 384, no. 37.-- Sow. Gen. Luce.— Desh. in Lam. loc. cit. p. 318, (2).— Forbes &§ Hanl. Br. Moll. vol. ii. p. 64.—B. M. Cat. Cuba Moll. p. 41, no. 499. This abundant W. Indian shell will not be received by many as belonging to the Pacific fauna. I can only say that 1 found the specimen, papered and numbered in the Dosinia box, per- fectly fresh, and bearing every mark of having been taken alive.