456:
495:
439:
985:
979:
973:
478:
422:
405:
38:
20:
524:
520:) have a simple aperture with a sharp edge, but after reaching adult size the aperture of the shell finally acquires adult characters, consisting of a thickened, reflected, inflected or lipped edge, which is sometimes more or less contracted by inflected calcareous projections known as teeth. These teeth may be outer lip teeth, columellar teeth or parietal teeth.
593:
693:
455:
260:
669:
383:
284:
1220:
657:
645:
339:
137:
The aperture of many snail shells is more or less round, rounded, elliptical or oval. This shape usually corresponds roughly to the cross-section of the
841:
377:
333:
681:
1225:
633:
236:
96:
494:
743:
1352:
145:
531:
Folds or plicae are named by their position in the aperture, as follows. The numbers refer to those in the diagram shown opposite:
106:
As well as the aperture, some gastropod shells have additional openings in their shells for respiration; this is the case in some
477:
438:
62:: it is the main opening of the shell, where the head-foot part of the body of the animal emerges for locomotion, feeding, etc.
404:
228:
The aperture is descending or deflected, when it does not follow the spiral of the shell, but turns downwards (such as in
103:
Scaphopod shells are tubular, and thus they have two openings: a main anterior aperture and a smaller posterior aperture.
1028:
421:
159:
The growth of the shell is provided for by non-continuous addition of minute layers to the aperture margin (also called
1701:
187:. When the aperture is called holostomatous, this means that the aperture is rounded or entire, uninterrupted by the
1706:
1621:
736:
984:
978:
1345:
972:
1646:
1636:
1711:
1676:
1013:
1783:
1742:
729:
713:
130:
gastropods, the aperture of the shell can be closed, and even completely sealed, with a sort of door or
94:
shells, where a natural opening between the two shell valves in the closed position is usually called a
1788:
1338:
1033:
1023:
1215:
1210:
1778:
1641:
278:
194:
For convenience of reference, the margin of a gastropod aperture is divided into three areas:
1519:
1398:
1317:
468:
214:
183:); very frequently it is interrupted, the left side of the aperture being formed only by the
131:
831:
484:
1305:
8:
1737:
1666:
1631:
1478:
1443:
1289:
1054:
944:
929:
908:
893:
761:
708:
118:(abalones) where the row of respiratory openings in the shell are also called orifices.
1656:
463:
29:
924:
1691:
1595:
1550:
1433:
1158:
1093:
153:
16:
Main opening of the shell, where the head-foot part of the body of the animal emerges
1681:
1605:
1600:
1565:
1473:
1393:
1313:
1284:
1194:
1083:
1073:
998:
993:
903:
878:
527:
Scheme of an aperture of a gastropod showing terminology of teeth, plicae and folds
428:
43:
322:
transverse, when its greatest diameter is at a right angle to the axis of volution
1493:
1488:
1483:
1468:
1463:
1403:
1370:
1179:
1151:
1141:
1136:
1124:
1109:
1049:
954:
898:
816:
502:
445:
411:
361:
70:
48:
24:
234:). Sometimes it departs from contact with the preceding whorl (as frequently in
1661:
1651:
1626:
1545:
1458:
1453:
1408:
1383:
1246:
1068:
1059:
1018:
883:
873:
614:
609:
366:
353:
218:
203:
188:
111:
592:
311:
longitudinal, when its greatest diameter is parallel with the axis of volution
1772:
1752:
1271:
821:
163:) from the mantle border, the principal agent in the secretion of the shell.
156:, which help make the soft parts of the animal less vulnerable to predation.
107:
59:
1418:
1230:
1129:
888:
788:
348:
patulous, when dilated and then compressed, when diminished at its entrance
270:
19:
37:
1747:
1732:
1686:
1585:
1428:
1184:
939:
517:
254:
127:
1696:
1671:
1590:
1580:
1509:
1448:
1438:
1388:
1361:
1321:
1276:
1088:
1078:
826:
783:
752:
291:
184:
149:
144:
The aperture of a snail shell can have many other forms: semicircular,
138:
115:
325:
oblique, when the greatest diameter is oblique to the axis of volution
224:
The palatal wall: the outer free wall of the final whorl of the shell.
1727:
1514:
1423:
1309:
1251:
949:
798:
793:
721:
516:
The shells of juveniles in some species (especially some families of
179:
173:
74:
1330:
1560:
1174:
1146:
391:
84:
79:
1757:
1064:
836:
523:
299:
91:
1570:
1555:
1529:
1189:
316:
171:
The margin of the aperture is sometimes continuous or entire (
1575:
1524:
1413:
934:
305:
230:
152:. In some gastropods, the aperture is narrowed by protruding
328:
oblong, much longer than it is wide, rounded above and below
202:): the area next to the penultimate whorl of the shell. The
110:(keyhole limpets) where the central smaller opening at the
248:
The shape of the aperture in a gastropod shell can be:
709:
Volume 25. Pupillidae (Gastrocoptinae, Vertigininae)
359:rounded, the circle slightly interrupted; example:
694:"Aperture shape Taller than wide, top angle acute"
1770:
707:Manual of Conchology. Second series: Pulmonata.
351:quadrate, roughly square or rectangular, as in
314:lunate, semilunar, semicircular or half-moon
114:of the shell is called an orifice, and in the
47:, which has a large aperture and a pronounced
1346:
737:
209:The columellar wall with the columellar lip (
705:Pilsbry H. A. & Cooke C. M. 1918-1920.
1353:
1339:
744:
730:
591:
522:
36:
18:
177:), or becomes continuous in the adult (
1771:
751:
369:but simply an opening for respiration.
198:The parietal wall with the outer lip (
1360:
1334:
725:
375:with the top angle acute - examples:
33:with the apertural view in the center
1024:Flotation devices ("secondary fins")
191:, notch, or by any other extension
13:
1316:) → Juvenile → Subadult → Adult •
58:is an opening in certain kinds of
14:
1800:
1702:Reproductive system of gastropods
670:"Aperture shape Oval or teardrop"
90:The word is not used to describe
1707:Respiratory system of gastropods
1622:Circulatory system of gastropods
1060:Hepatopancreas (digestive gland)
983:
977:
971:
493:
476:
454:
437:
420:
403:
121:
69:is used for the main opening in
1029:Funnel–mantle locking apparatus
415:has a long and narrow aperture.
1647:Excretory system of gastropods
1637:Digestive system of gastropods
1216:Nuchal folds (occipital folds)
1211:Nuchal crest (occipital crest)
699:
687:
675:
663:
651:
639:
627:
266:circular, rotundate, orbicular
166:
1:
620:
511:
331:oval or teardrop - examples:
1712:Sensory organs of gastropods
1677:Nervous system of gastropods
1322:Protoconch (embryonic shell)
488:has a semicircular aperture.
365:. Consequently, there is no
276:crescent-shaped - examples:
269:claw-shaped aperture - Some
252:auriform, ear-shaped, as in
7:
1743:Circumesophageal nerve ring
603:
273:have a claw-shaped aperture
10:
1805:
696:. accessed 3 January 2011.
684:. accessed 3 January 2011.
672:. accessed 3 January 2011.
660:. accessed 3 January 2011.
658:"Aperture shape Half-moon"
636:. accessed 3 January 2011.
1720:
1614:
1538:
1502:
1369:
1300:
1264:
1239:
1203:
1167:
1117:
1106:
1042:
1006:
992:
969:
917:
861:
854:
809:
776:
769:
760:
648:. accessed 3 January 2011
646:"Aperture shape Crescent"
596:The dentate aperture of
294:has a distorted aperture
243:
221:is situated at its base.
213:): the wall next to the
567:
500:Some shells, like this
449:has a rounded aperture.
261:Aerotrochus perdepressa
206:is situated at the top.
682:"Aperture shape Round"
600:
564:are named as follows:
528:
279:Hyalosagda arboreoides
258:* bean - for example:
51:
34:
1303:Developmental stages:
1195:Spadix and antispadix
1079:Nephridia ("kidneys")
634:"Aperture shape Bean"
598:Multidentula ovularis
595:
526:
467:can be covered by an
432:has an oval aperture.
290:distorted aperture -
77:shells, and also for
40:
22:
485:Theodoxus danubialis
461:Rounded aperture of
384:Varicella griffithii
285:Dialeuca conspersula
1667:Hypobranchial gland
1615:Internal soft parts
1539:External soft parts
1290:Squid giant synapse
506:, have no aperture.
397:without an aperture
1784:Cephalopod zootomy
1221:Occipital membrane
1094:Pericardial glands
789:Argonautid eggcase
601:
529:
464:Valvata piscinalis
389:triangular, as in
52:
35:
30:Norelona pyrenaica
1789:Gastropod anatomy
1766:
1765:
1692:Oesophageal pouch
1551:Caudal mucous pit
1328:
1327:
1260:
1259:
1159:Suckers and hooks
1102:
1101:
1084:Nidamental glands
1014:Dermal structures
967:
966:
963:
962:
850:
849:
345:ovate, egg-shaped
340:Urocoptis ambigua
23:Three views of a
1796:
1682:Nidamental gland
1606:Suprapedal gland
1503:Other hard parts
1355:
1348:
1341:
1332:
1331:
1314:Doratopsis stage
1285:Squid giant axon
1204:Occipital region
1115:
1114:
1055:Ctenidia (gills)
1050:Branchial hearts
1043:Internal anatomy
1007:External anatomy
1004:
1003:
987:
981:
975:
859:
858:
774:
773:
767:
766:
746:
739:
732:
723:
722:
716:
712:. Philadelphia.
703:
697:
691:
685:
679:
673:
667:
661:
655:
649:
643:
637:
631:
584:angular and twin
497:
480:
458:
441:
429:Indrella ampulla
424:
407:
378:Leptopeas micrum
334:Geomelania minor
297:linear, narrow.
71:gastropod shells
44:Semicassis pyrum
1804:
1803:
1799:
1798:
1797:
1795:
1794:
1793:
1779:Mollusc anatomy
1769:
1768:
1767:
1762:
1716:
1657:Hancock's organ
1610:
1534:
1498:
1469:Stromboid notch
1365:
1359:
1329:
1324:
1296:
1281:Nervous system
1256:
1235:
1226:Olfactory organ
1199:
1163:
1108:
1098:
1038:
997:
988:
982:
976:
959:
913:
846:
817:Belemnoid guard
805:
794:Nautiloid shell
756:
750:
720:
719:
704:
700:
692:
688:
680:
676:
668:
664:
656:
652:
644:
640:
632:
628:
623:
606:
590:
575:supracolumellar
569:infracolumellar
559:
535:Folds or plicae
514:
507:
503:Patella vulgata
498:
489:
481:
472:
459:
450:
446:Valvata sincera
442:
433:
425:
416:
412:Conus betulinus
408:
362:Valvata sincera
246:
169:
124:
49:parietal callus
17:
12:
11:
5:
1802:
1792:
1791:
1786:
1781:
1764:
1763:
1761:
1760:
1755:
1750:
1745:
1740:
1735:
1730:
1724:
1722:
1718:
1717:
1715:
1714:
1709:
1704:
1699:
1694:
1689:
1684:
1679:
1674:
1669:
1664:
1662:Hepatopancreas
1659:
1654:
1652:Gastric shield
1649:
1644:
1639:
1634:
1629:
1624:
1618:
1616:
1612:
1611:
1609:
1608:
1603:
1598:
1596:Semper's organ
1593:
1588:
1583:
1578:
1573:
1568:
1563:
1558:
1553:
1548:
1546:Caryophyllidia
1542:
1540:
1536:
1535:
1533:
1532:
1527:
1522:
1517:
1512:
1506:
1504:
1500:
1499:
1497:
1496:
1491:
1486:
1481:
1476:
1471:
1466:
1461:
1459:Siphonal notch
1456:
1454:Siphonal canal
1451:
1446:
1441:
1436:
1431:
1426:
1421:
1416:
1411:
1406:
1401:
1396:
1391:
1386:
1381:
1375:
1373:
1367:
1366:
1358:
1357:
1350:
1343:
1335:
1326:
1325:
1301:
1298:
1297:
1295:
1294:
1293:
1292:
1287:
1279:
1274:
1272:Chromatophores
1268:
1266:
1262:
1261:
1258:
1257:
1255:
1254:
1249:
1243:
1241:
1237:
1236:
1234:
1233:
1228:
1223:
1218:
1213:
1207:
1205:
1201:
1200:
1198:
1197:
1192:
1187:
1182:
1177:
1171:
1169:
1165:
1164:
1162:
1161:
1156:
1155:
1154:
1149:
1144:
1134:
1133:
1132:
1121:
1119:
1118:Brachial crown
1112:
1104:
1103:
1100:
1099:
1097:
1096:
1091:
1086:
1081:
1076:
1071:
1062:
1057:
1052:
1046:
1044:
1040:
1039:
1037:
1036:
1031:
1026:
1021:
1016:
1010:
1008:
1001:
990:
989:
970:
968:
965:
964:
961:
960:
958:
957:
952:
947:
942:
937:
932:
927:
921:
919:
915:
914:
912:
911:
906:
901:
896:
891:
886:
881:
876:
871:
865:
863:
856:
852:
851:
848:
847:
845:
844:
839:
834:
829:
824:
819:
813:
811:
807:
806:
804:
803:
802:
801:
791:
786:
784:Ammonoid shell
780:
778:
771:
764:
758:
757:
749:
748:
741:
734:
726:
718:
717:
698:
686:
674:
662:
650:
638:
625:
624:
622:
619:
618:
617:
615:Siphonal canal
612:
610:Siphonal notch
605:
602:
589:
588:
585:
582:
579:
576:
573:
570:
566:
558:
557:
554:
551:
548:
545:
542:
538:
513:
510:
509:
508:
499:
492:
490:
482:
475:
473:
460:
453:
451:
443:
436:
434:
426:
419:
417:
409:
402:
399:
398:
395:
387:
373:
370:
367:siphonal canal
357:
354:Architectonica
349:
346:
343:
329:
326:
323:
320:
312:
309:
295:
288:
274:
267:
264:
245:
242:
226:
225:
222:
219:siphonal canal
207:
204:siphonal notch
189:siphonal canal
168:
165:
141:of the shell.
123:
120:
60:mollusc shells
15:
9:
6:
4:
3:
2:
1801:
1790:
1787:
1785:
1782:
1780:
1777:
1776:
1774:
1759:
1756:
1754:
1753:Tyrian purple
1751:
1749:
1746:
1744:
1741:
1739:
1736:
1734:
1731:
1729:
1726:
1725:
1723:
1719:
1713:
1710:
1708:
1705:
1703:
1700:
1698:
1695:
1693:
1690:
1688:
1685:
1683:
1680:
1678:
1675:
1673:
1670:
1668:
1665:
1663:
1660:
1658:
1655:
1653:
1650:
1648:
1645:
1643:
1640:
1638:
1635:
1633:
1630:
1628:
1625:
1623:
1620:
1619:
1617:
1613:
1607:
1604:
1602:
1599:
1597:
1594:
1592:
1589:
1587:
1584:
1582:
1579:
1577:
1574:
1572:
1569:
1567:
1564:
1562:
1559:
1557:
1554:
1552:
1549:
1547:
1544:
1543:
1541:
1537:
1531:
1528:
1526:
1523:
1521:
1518:
1516:
1513:
1511:
1508:
1507:
1505:
1501:
1495:
1492:
1490:
1487:
1485:
1482:
1480:
1477:
1475:
1472:
1470:
1467:
1465:
1462:
1460:
1457:
1455:
1452:
1450:
1447:
1445:
1442:
1440:
1437:
1435:
1432:
1430:
1427:
1425:
1422:
1420:
1417:
1415:
1412:
1410:
1407:
1405:
1402:
1400:
1397:
1395:
1392:
1390:
1387:
1385:
1382:
1380:
1377:
1376:
1374:
1372:
1368:
1363:
1356:
1351:
1349:
1344:
1342:
1337:
1336:
1333:
1323:
1319:
1315:
1311:
1307:
1304:
1299:
1291:
1288:
1286:
1283:
1282:
1280:
1278:
1275:
1273:
1270:
1269:
1267:
1263:
1253:
1250:
1248:
1245:
1244:
1242:
1238:
1232:
1229:
1227:
1224:
1222:
1219:
1217:
1214:
1212:
1209:
1208:
1206:
1202:
1196:
1193:
1191:
1188:
1186:
1183:
1181:
1178:
1176:
1173:
1172:
1170:
1168:Buccal region
1166:
1160:
1157:
1153:
1150:
1148:
1145:
1143:
1140:
1139:
1138:
1135:
1131:
1128:
1127:
1126:
1123:
1122:
1120:
1116:
1113:
1111:
1105:
1095:
1092:
1090:
1087:
1085:
1082:
1080:
1077:
1075:
1074:Needham's sac
1072:
1070:
1066:
1063:
1061:
1058:
1056:
1053:
1051:
1048:
1047:
1045:
1041:
1035:
1032:
1030:
1027:
1025:
1022:
1020:
1017:
1015:
1012:
1011:
1009:
1005:
1002:
1000:
995:
991:
986:
980:
974:
956:
953:
951:
948:
946:
943:
941:
938:
936:
933:
931:
928:
926:
923:
922:
920:
916:
910:
907:
905:
902:
900:
897:
895:
892:
890:
887:
885:
882:
880:
877:
875:
872:
870:
867:
866:
864:
860:
857:
853:
843:
840:
838:
837:Spirula shell
835:
833:
832:Gladius (pen)
830:
828:
825:
823:
822:Cirrate shell
820:
818:
815:
814:
812:
808:
800:
797:
796:
795:
792:
790:
787:
785:
782:
781:
779:
775:
772:
768:
765:
763:
759:
754:
747:
742:
740:
735:
733:
728:
727:
724:
715:
711:
710:
702:
695:
690:
683:
678:
671:
666:
659:
654:
647:
642:
635:
630:
626:
616:
613:
611:
608:
607:
599:
594:
586:
583:
580:
578:infraparietal
577:
574:
571:
568:
565:
563:
555:
552:
550:lower palatal
549:
546:
544:upper palatal
543:
540:
539:
537:
536:
532:
525:
521:
519:
505:
504:
496:
491:
487:
486:
479:
474:
470:
466:
465:
457:
452:
448:
447:
440:
435:
431:
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122:In gastropods
119:
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108:Fissurellidae
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1419:Periostracum
1378:
1302:
1231:Nuchal organ
1130:Hectocotylus
1019:Fins (wings)
925:Body chamber
889:Periostracum
868:
706:
701:
689:
677:
665:
653:
641:
629:
597:
561:
560:
553:infrapalatal
547:interpalatal
541:suprapalatal
534:
533:
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483:
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390:
382:
376:
372:semicircular
360:
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271:Melongenidae
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1748:Trochophore
1733:Pseudofeces
1687:Odontophore
1642:Diverticula
1586:Pneumostome
1429:Planispiral
1318:Egg fossils
1277:Photophores
1240:Other parts
1185:Odontophore
1107:Head &
940:Phragmocone
518:land snails
255:Auriculella
237:Cylindrella
167:Terminology
128:prosobranch
41:A shell of
1773:Categories
1697:Osphradium
1672:Nephridium
1591:Rhinophore
1581:Parapodium
1510:Clausilium
1449:Selenizone
1439:Protoconch
1389:Body whorl
1252:Statocysts
1089:Osphradium
827:Cuttlebone
753:Cephalopod
621:References
572:columellar
512:With teeth
292:Personidae
185:body whorl
150:auriculate
139:body whorl
116:Haliotidae
1728:Epiphragm
1632:Ctenidium
1520:Operculum
1515:Love dart
1479:Umbilicus
1444:Sculpture
1424:Peristome
1399:Columella
1362:Gastropod
1310:Paralarva
1137:Tentacles
950:Siphuncle
909:Umbilicus
894:Sculpture
799:Orthocone
714:Page vii.
469:operculum
215:columella
180:Caracolus
174:Epitonium
161:peristome
146:trilobate
132:operculum
75:scaphopod
65:The term
1561:Cnidosac
1379:Aperture
1175:Aptychus
1147:Dactylus
918:Internal
869:Aperture
862:External
855:Features
810:Internal
777:External
604:See also
587:paraller
581:parietal
562:Lamellae
392:Janthina
126:In some
87:shells.
85:ammonite
80:Nautilus
67:aperture
56:aperture
1758:Veliger
1738:Torsion
1364:anatomy
1265:General
1065:Ink sac
930:Camerae
904:Sutures
755:anatomy
300:Cypraea
92:bivalve
1601:Siphon
1571:Mentum
1566:Mantle
1556:Cerata
1530:Radula
1474:Suture
1394:Callus
1190:Radula
1142:Carpus
999:funnel
996:&
994:Mantle
955:Whorls
879:Callus
842:Stylet
317:Nerita
217:. The
211:labium
200:labrum
154:plaits
1721:Other
1576:Notum
1525:Pearl
1494:Whorl
1489:Varix
1484:Valve
1464:Spire
1434:Plait
1414:Nacre
1371:Shell
1306:Spawn
1152:Manus
1110:limbs
945:Septa
935:Nacre
899:Spire
884:Lirae
770:Types
762:Shell
556:basal
306:Conus
244:Shape
231:Helix
25:shell
1627:Crop
1409:Lira
1384:Apex
1247:Eyes
1180:Beak
1125:Arms
1067:and
1034:Tail
874:Apex
112:apex
97:gape
83:and
54:The
1404:Lip
1069:ink
148:or
27:of
1775::
1320:•
1308:→
381:,
337:,
303:,
282:,
240:.
134:.
100:.
73:,
1354:e
1347:t
1340:v
1312:(
745:e
738:t
731:v
471:.
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