OCR Text |
Show 356 MOLLUSCA. have three filaments on each edge of the mantle, Ol' at least some appendages to the 5idcs of th: ~eet. . . Of those that have no umb1hcus, there are some m wluch the co. lumella, that has the form of a concave arch, is continuous with the external margin, without any projection. It is the angle and projec. tion of this ma1·gin which distinguishes them from Turbo-TECTA· nxuM, Montf. ( 1) Several are flattened, with a trenchant edge, which has caused them to be compared to the rowel of a spur-CALCAR, Montf.(2) Some again are slightly depressed, orbicular and shining, with a semi-round aperture, the columella convex and callous-RoTELLA, Lam.(3) The columella of others is distinguished near the base by a little prominence, or vestige of a tooth, similar to that of the Monodontes, from which these Trochi only differ in the angle of their aperture, and the projection of their margin. The aperture is usually about as high as it is wide-CANTHARis, Montf.( 4) In some of them, on the contrary, the aperture is much wider than it is high, and their convex base approximates them to theCa· Iyptracea-lNFUNDIBULUM, Montf.( s) . . .. In others again, where the aperture IS also much w1der than 1t1s high, the columella forms a spiral canal(6). . . Those which have a turreted shell approach Cerithtum-TELE· SOOPIUM, Montf.(7) Among the umbilicated Trochi, there are some in which thereis no projection in the columella; most of them are flattened, and have the external angle trenchant. Of this number is Tr. agglutinans, L.; Chemn., V, clxxii, 1688, 9. Remarka· ble for the habit of glueing to its shell, and even incorporating (1) Troclt. inermis, Chemn., V, clxxiii, 1712-13;-T1·. Coolcii, Id., clxi,·, 1551;-Tr. c:elatus, Id., clxii, 1536-37;-Tr. imbricatus, Ib., 1532-33;-Tr. tuber, Id., clxv, 1573-74;-Tr. sinensi.s, lb., 1564-65;-Tw·bo pagodus, Jd., clxiii, 1541-4~;-Turbo tectum-persicum, lb., 1543-44. . ~ (2) 'J'Iurbo calcar, L., Chemn., V, clxiv, 1552;-T stellans, Icl., 155.>;-T. acu· leatus, Icl., 1554-57;-T. imperialis, ld., 1714. (3) Tr. vestiarius, L., Chemn., V, clxvi, 1601. T: (4) Tr. iris, Chemn., 1522-23;-Tr. granatf,lm, lb., 1654-55;- r. r:yzypht·n us, I b ., cl xv1· , 1 59 C..). -98 ;-T:r . conus, c l xv.u. , 1610' ·-Tr· maculatuJ, clxviii, 1617-18;-Tr. americanusJ clxii, 1534-35;-Tr. conulus, Gua 1t. , LXX,M. ( 5) Trockus concavus, Chemn., V, clxxviii, 1620, 21. . . Id (6) T rochus "oveolatus Chemn V clxi 1516-19;-Tr. maunttanus, ., J' ' ·' ' ' · lx 1510 cb:iii, 1547-48;-Tr. fenestratus, lb., 1549-50;-Tr. obehscus, c ' -12. (7) Trochus telescopium, Chemn., V, clx, 1507-9. GASTEROPODA PECTINIBRANCIIIAT A. 357 with it, as fast as it increases in size, various foreign bodies such as little pebbles , fragments of other shells, &c.; it fre: quently covers its umbilicus with a testaceous plate(!). The margin of others, however, is rounded, such as Tr. cinerarius, L.; Chemn., V, clxxi, 1686. A small species, and the most common on the coast of France; greenish, obliquely streaked with violet. Some umbilicated Trochi have a prominence near the bottom of the columella(2), And, finally, there are others in which it is longitudinally ere· nate( 3). The SoLARiuM, Lam. Is distinguished from all other Trochi by a very broad conical spire, at the base of which is an extremely wide umbilicus in which may be seen the internal edges of all the whorls, marked by a crenated cord(4). EvoMPHALus, Sowerby. Fossil shells resembling a Solarium, but wanting the dentations on the internal whorls of the umbilicus(5). The genus ·TuRBo, Lin.(6) Comprehends all the species with a completely and regularly turbinated shell, and a perfectly round aperture. Close observation has caused them to be greatly subdivided. In the . TuRBo, Lam. 'fhe shell is round or oval, and thick; the aperture completed on the side next to the spire, by the penultimate whorl. The animal (1) Add; Trocltus indicus, Chemn., V, clxxii, 1697-98;-Tr. imperialis, clxxiii, 1714, and clxxiv, 1715;-Tr. solaris, lb., 1701-1702, and 1716-1717; -Tr. planus, lb., 1721, 1722. (2) Tr. virgatus, Chemn., V, clx, 1514-15;-Tr. niloticus, Chemn., V, clxvii, 1605-7, clxviii, 1614;-Tr. vernus, Jd., clxix, 1625-26;-Tr. incequalis, clxx, 1636-37;-Tr. ma!jnus, clxxi, 1656-57;-Tr. consperstes, Gualt., Ixx, B.;-Tr. jujubinus, clxvii, 1612-13. (3) 1'r. maculatus, clxviii, 1615-1616;-Tr. costattes, clxix, 1634;-Tr. viridis, clxx, 1644;-Tr. radiatus, lb., 1640-42. (4) Tr. pe:rspectivus, L. Chemn., V, clxxii, 1691-96;-Tr. stramineus, Ib., 1699;-Tr. variegatus, lb., 1708-1709;-Tr. infundibuliformis, lb., 1706-1707. (5) Evomphaluspentangulattes, Sowerb., Min. Conch., T, pl. xlv, f. 2;-Ev. notkJsu. s, Id., xlvi, &c. (6) This gre~t genus constitutes the family CmcosTo~rA of Blainviiic. |