441:
476:
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20:
38:
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220:
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137:
of the shell when the soft parts of the animal are retracted. The shape of the operculum varies greatly from one family of gastropods to another. It is fairly often circular, or more or less oval in shape. In species where the operculum fits snugly, its outline corresponds exactly to the shape of the
723:
of North
America, as detailing in masks, panels and paddles. These objects are used to represent the teeth in masks, and are used as a decorative element in many of the objects which play an important part in the art and culture of Northwest Coast peoples, including dishes for food, bentwood boxes,
711:
species are also used. The operculum has two sides of differing appearance. Either side or both may be displayed as jewelry or ornament. The internal side is flat and white, with a spiral suture line, while the external side is hemispherical, glossy, and variously colored and patterned. In the case
504:
The most common kind of operculum is composed of a thin to rather thick corneous protein material, which is yellow to brownish in color and is usually somewhat translucent. This matter is supple when in its natural state but may become brittle when it is dried out. The operculum varies in shape,
540:
The different shapes of opercula can include ungulate (hooflike), claw-like, or ovate. The type and shape of the operculum is used to help identify and classify related groups (genera) of land operculates, and likewise some marine operculates.
288:
In many species of marine shelled snails which live subtidally, the operculum is greatly reduced in size, and no longer serves to seal the shell entrance. In a large number of families it has been eliminated completely.
187:
species, then for many years after that they were considered to be a form of paired or single operculum-like structures belonging to ammonites. More recently the aptychus or paired aptychi have been hypothesized to be a
510:
260:, with mostly distinct nuclei, and long divided processes enter between the muscular fibres. The operculum, a cuticular development of these cells, is composed, as may be seen in the corneous opercula of
440:
168:, a temporary structure that can in some cases serve some of the same functions as an operculum. The epiphragm may be distinguished from the true operculum by its homogeneity and want of growth marks.
962:. This site also provides fairly extensive material on the growth, development, and physiology of the gastropod operculum as well as dozens of pictures of both the operculum and its host shell.
490:
type 1: flexiclaudent spiral (mostly multispiral) operculum; its shape does not coincide with the aperture but fits by flexing into the aperture; predominantly present in archaeogastropods.
204:. This is very important in intertidal marine snails during low tide, and this also enables operculate freshwater and land snails to survive periods of drought and dry weather.
399:
determined by the number of whorls in the shell, but by the curvature of the aperture, and the necessity that the operculum should revolve fast enough to fit it constantly.
493:
type 2: rigiclaudent spiral (usually paucispiral) operculum; its shape fitting the aperture; present in archaeogastropods, but predominating in
Caenogastropoda.
412:
475:
458:
145:
Many families have opercula that are reduced in size, and which are not capable of closing the shell aperture. Opercula have sometimes been modified: in the
422:
496:
type 3: rigiclaudent concentric operculum; its shape fitting the aperture; predominant in higher neotaenioglossans and exclusive in neogastropods.
536:
overlay. The calcareous surface in some genera has color or ornamentation of various kinds including, for example, pustules and incised grooves.
285:
size. In many species, when the animal is active and crawling, part of the underside of the shell rests on the outer surface of the operculum.
133:
The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of "trapdoor" to close the
1002:
796:
Checa, Antonio G.; Jiménez-Jiménez, Antonio P. (1998). "Constructional
Morphology, Origin, and Evolution of the Gastropod Operculum".
296:, the operculum is elongated and sickle-shaped, and is used to dig into the sand to enable the conch to perform a leaping type of
643:
shell/armour fragrance) respectively. Incense producers in these countries use the operculum of many conches and other marine
886:
663:
smell. The clean opercula are then ground to a powder and used as a scent fixative, in a technique similar to that used in
647:, including those found in Southeast Asia, South America, and East Africa. The opercula are traditionally treated with
959:
698:" in rings, bracelets, amulets etc. These opercula are commonly known as "cats eye" (or more recently "Shiva's eye").
1351:
1356:
1271:
207:
In those marine species where the operculum completely seals the shell, it can also serve as a protection against
995:
1296:
1286:
278:, of very thin superimposed layers. The cylindrical cells are attached with their head to the lowermost layer.
200:
Perhaps the most essential function of the operculum in gastropods is to allow snails to resist drying out, or
738:, chains and girdles composed of the coloured opercula of certain shells were considered valuable ornaments.
1361:
1326:
369:
spiral: when it grows only on one edge, and revolves as it grows; it is always sinistral in dextral shells.
250:
muscle with an opercular disc dorsally to the upper surface of the posterior part of the foot. However, in
242:
showing how the back of the shell rests on the round operculum on top of the foot as the snail moves along
1392:
780:
842:
307:
Various forms of opercula in Pyrula; Purpura; Littorina; Aulopoma; Torinia; Neritopsis; Strombus; Conus
1443:
1428:
988:
1438:
1433:
466:
281:
The operculum grows in size as the shell grows, such that the operculum remains in proportion to the
149:
the operculum is claw-shaped and is used to push into the substrate in a leaping form of locomotion.
871:
410:
radiated is a modification of the articulated operculum in which the spiral is not so evident as in
776:
509:
16:
Hard structure which closes the aperture of a gastropod when the animal retreats into the shell
1291:
798:
515:
1048:
430:
247:
330:
imbricated, or lamellar: when it grows only on one side, and the nucleus is marginal, as in
896:
807:
448:
238:
844:
Zoologische
Anmerkungen zu zwei minoischen SiegelabdrĂŒcken mit einem Tritonshorn (Gattung
8:
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720:
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268:
46:
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The other kind of operculum is restricted to a few families of gastropods including the
395:
where they sometimes amount to twenty; the number of turns which the operculum makes is
303:
1306:
1028:
859:
823:
383:
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274:
161:
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snails are inoperculate, i.e. they do not have an operculum, with the exception of the
139:
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37:
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25:
179:(plural aptychi) existed. When these were first described they were thought to be
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41:
19:
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depending on the family of snails and the shape of the aperture of their shells.
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59:
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There are two basic types of opercula in terms of their material composition:
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945:
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556:
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115:
549:
The oldest known human depiction of an operculum together with the shell of
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317:
446:
Example of a polygyrous spiral with eccentric nucleus in the operculum of
1397:
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claw-shaped, or unguiculate: with the nucleus apical or in front, as in
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87:
30:
110:, and in a minority of terrestrial gastropods, including the families
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multispiral or polygyrous: having many closely spaced spirals as in
374:
342:
336:
165:
153:
107:
95:
980:
327:, and in other the nucleus is near the parietal margin of the shell.
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When burnt on its own, high quality operculum reportedly smells of
593:
363:
252:
208:
176:
175:(extinct shelled cephalopods), a calcareous structure known as the
172:
91:
83:
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707:
is the species whose operculum is most renowned, although other
1220:
1205:
1179:
892:
716:
there is a prominent dark 'eye' and sometimes a greenish area.
609:
481:
Fossil spiral opercula (both sides) from the
Pliocene of Cyprus
404:
142:
of the shell and it serves to seal the entrance of the shell.
1225:
1174:
1063:
668:
656:
644:
624:
620:
486:
In 1998 Checa and
Jimeneze proposed three types of opercula:
357:
293:
262:
682:, while that of lower quality is reminiscent of burnt hair.
532:. This operculum structure has a corneous base with a heavy
311:
The structure of the operculum can be described as follows:
941:
Animal: The
Definitive Visual Guide to the World's Wildlife
679:
660:
584:
236:
A photo of an individual of the freshwater snail species
189:
246:
In life, the operculum is attached at the ending of the
315:
concentric: the nucleus is central or subcentral as in
228:
near Goat Island, New
Zealand, with a damaged operculum
106:; the structure is found in some marine and freshwater
685:
795:
619:
Operculum powder is also an important ingredient in
372:paucispiral or oligogyrous: with few spirals as in
694:is sometimes used as a very inexpensive organic "
1420:
164:pulmonate species are capable of secreting an
996:
402:articulated, when it has a projection, as in
94:that exists in many (but not all) groups of
785:. Philadelphia, The author. pp. 47â48.
775:
612:incense material which is described in the
604:are most commonly used in regions near the
1003:
989:
840:
937:
608:. Opercula from these conches may be the
591:cultures. The operculum of conch species
884:
508:
302:
231:
218:
36:
18:
771:
769:
1421:
960:Pictures of diverse gastropod opercula
566:
1010:
984:
782:Structural and systematic conchology
766:
690:The operculum of certain species of
627:incense making. Here it is called "
464:Example of an oligogyrous spiral in
428:Example of a concentric operculum (
361:; it is claw-shaped and serrated in
71:
13:
741:
686:As a gemstone or decorative object
211:when the snail body is retracted.
14:
1455:
1352:Reproductive system of gastropods
953:
516:Tropidophora fimbriata haemostoma
381:subspiral or scarcely spiral, in
1357:Respiratory system of gastropods
1272:Circulatory system of gastropods
575:, especially varieties from the
513:An individual of the land snail
474:
457:
439:
421:
50:with corneous operculum in place
1297:Excretory system of gastropods
1287:Digestive system of gastropods
910:
878:
834:
789:
102:, and also in a few groups of
1:
759:
544:
1362:Sensory organs of gastropods
1327:Nervous system of gastropods
256:a layer of long cylindrical
195:
90:anatomical structure like a
7:
1393:Circumesophageal nerve ring
719:Opercula are often used in
10:
1460:
965:Photo of opercula of some
734:reported in 1896 that, in
214:
1370:
1264:
1188:
1152:
1019:
820:10.1017/S0094837300020005
635:sea shell fragrance) or "
579:, have long served as an
467:Cremnoconchus syhadrensis
70: 'cover, covering';
746:The largest opercula of
192:apparatus of ammonites.
44:of the freshwater snail
659:in order to remove any
888:The History of Mankind
732:The History of Mankind
587:tradition, as well as
524:
308:
243:
229:
64:
51:
34:
23:Shell of marine snail
512:
431:Filopaludina martensi
306:
235:
222:
40:
22:
583:material in ancient
571:Opercula of certain
449:Marstonia comalensis
239:Bithynia tentaculata
1317:Hypobranchial gland
1265:Internal soft parts
1189:External soft parts
946:DK Adult Publishing
920:. manandmollusc.net
841:Schifko G. (2005).
812:1998Pbio...24..109C
721:Northwest Coast art
667:with certain plant
567:As incense material
561:Minoan civilization
452:, scale bar: 200 ÎŒm
47:Viviparus contectus
938:Burnie, D (2001).
752:have been used as
594:Strombus tricornis
525:
309:
244:
230:
52:
35:
33:operculum in place
1444:Organic gemstones
1429:Gastropod anatomy
1416:
1415:
1342:Oesophageal pouch
1201:Caudal mucous pit
885:Ratzel F (1896).
854:. pp. 27â33.
701:The turban snail
639:" (Japanese: çČéŠ,
552:Charonia tritonis
100:freshwater snails
1451:
1439:Mollusc products
1434:Incense material
1332:Nidamental gland
1256:Suprapedal gland
1153:Other hard parts
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749:Turbo marmoratus
728:Friedrich Ratzel
704:Turbo petholatus
678:or other animal
631:" (Chinese: èČéŠ;
478:
461:
443:
425:
258:epithelial cells
160:. However, some
73:
26:Lunella torquata
1459:
1458:
1454:
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742:As paperweights
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600:Lambis truncata
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42:Gastropod shell
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954:External links
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806:(1): 109â132.
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614:Book of Exodus
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948:. p. 24.
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1069:Periostracum
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922:. Retrieved
918:"Operculata"
912:
902:November 28,
900:. Retrieved
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799:Paleobiology
797:
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754:paperweights
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45:
24:
1398:Trochophore
1383:Pseudofeces
1337:Odontophore
1292:Diverticula
1236:Pneumostome
1079:Planispiral
974:Busycotypus
868:|work=
848:) als Motiv
777:Tryon G. W.
606:Middle East
202:desiccation
162:terrestrial
124:Maizaniidae
112:Helicinidae
104:land snails
1423:Categories
1347:Osphradium
1322:Nephridium
1241:Rhinophore
1231:Parapodium
1160:Clausilium
1099:Selenizone
1089:Protoconch
1039:Body whorl
760:References
692:Turbinidae
573:gastropods
545:Human uses
534:calcareous
530:Turbinidae
521:calcareous
352:Turbinella
324:Ampullaria
298:locomotion
248:columellar
147:Strombidae
128:Pomatiidae
120:Aciculidae
108:gastropods
96:sea snails
88:calcareous
80:operculums
58:(from
31:calcareous
1378:Epiphragm
1282:Ctenidium
1170:Operculum
1165:Love dart
1129:Umbilicus
1094:Sculpture
1074:Peristome
1049:Columella
1012:Gastropod
897:MacMillan
870:ignored (
860:cite book
676:castoreum
629:bĂši xiÄng
523:operculum
413:Navicella
375:Littorina
343:Paludomus
337:Xenophora
283:apertural
209:predators
196:Functions
173:ammonites
166:epiphragm
154:pulmonate
66:operculum
56:operculum
29:with the
1211:Cnidosac
1029:Aperture
846:Charonia
828:88680117
779:(1882).
696:gemstone
665:perfumes
625:Japanese
364:Strombus
253:Buccinum
177:aptychus
140:aperture
135:aperture
92:trapdoor
84:corneous
76:opercula
1408:Veliger
1388:Torsion
1014:anatomy
977:species
968:Busycon
808:Bibcode
736:Oceania
653:alcohol
649:vinegar
637:kai kou
621:Chinese
589:Arabian
581:incense
577:Red Sea
392:Trochus
332:Purpura
269:Purpura
215:Anatomy
185:bivalve
130:, etc.
82:) is a
1251:Siphon
1221:Mentum
1216:Mantle
1206:Cerata
1180:Radula
1124:Suture
1044:Callus
924:9 July
893:London
826:
669:resins
645:snails
610:onycha
585:Jewish
405:Nerita
384:Thiara
340:, and
294:conchs
275:Triton
181:valves
74:
1371:Other
1226:Notum
1175:Pearl
1144:Whorl
1139:Varix
1134:Valve
1114:Spire
1084:Plait
1064:Nacre
1021:Shell
852:(PDF)
824:S2CID
709:Turbo
680:musks
661:fishy
657:water
602:sebae
555:is a
358:Fusus
263:Murex
183:of a
62:
60:Latin
1277:Crop
1059:Lira
1034:Apex
971:and
926:2011
904:2009
872:help
655:and
641:lit.
633:lit.
623:and
597:and
557:seal
355:and
321:and
98:and
54:The
1054:Lip
816:doi
730:in
712:of
397:not
190:jaw
171:In
86:or
78:or
72:pl.
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