| Term | Definition |
| ADULT WHORLS | All whorls of a GASTROPOD shell beyond those of the nucleus, or PROTOCONCH; = TELEOCONCH; see also: NUCLEAR WHORL; PROTOCONCH. | |
| BODY WHORL |
The most recently formed WHORL of a gastropod shell, usually enclosing most of the animal's body. See illustration of Composite Gastropod. |
|
| EMBRYONIC WHORL | A single WHORL of the NUCLEUS or PROTOCONCH; the earliest portion of the LARVAL SHELL. | |
| NUCLEAR WHORL | The early larval shell, sometimes distinguished from the PROTOCONCH. See illustration: Composite Gastropod. See also: ADULT WHORLS; VELICONCH. | |
| PENULTIMATE WHORL | The next to the last WHORL, or the one before the BODY WHORL (of snails). | |
| PERIPHERY, WHORL | [need definition]. | |
| POSTNUCLEAR WHORL | Any turn of a GASTROPOD shell formed after the formation of the NUCLEUS. | |
| PRECEDING WHORL | The turn of a GASTROPOD shell just previous to the one being described. | |
| SPIRE WHORL | One turn (360 degrees) of the spire, exclusive of the BODY WHORL. | |
| WHORL | A single complete turn of 360 degrees in the spiral growth of a gastropod shell or OPERCULUM; see also: BODY WHORL; PENULTIMATE; PERIPHERY, (types); WHORL, (types); VOLUTION. | |
| WHORL PERIPHERY | The part of a GASTROPOD shell that is farthest from the AXIS of coiling; = WHORL PERIPHERY. See illustration: Composite Gastropod. See also: PERIPHERY, (types); WHORL, (types). | |
| WHORL, ANGULATE | Having the outer PERIPHERY of the whorl midway between CARINATE and rounded. | |
| WHORL, BICARINATE | Having two CARINA on the PERIPHERY of a whorl. | |
| WHORL, CARINATE | Having one or more CARINA on the PERIPHERY of a whorl; see also: WHORL, BICARINATE; WHORL, MONOCARINATE. | |
| WHORL, CONVOLUTE | Having the body WHORL of the shell expand abruptly so as to wrap around and conceal all the older, subsequent whorls as in Cyprea spp.. | |
| WHORL, DESCENDING | The lowering of the last stages of growth of the BODY WHORL. | |
| WHORL, DISCONTIGUOUS | Having subsequent WHORLS not touching the previous; = WHORL, DISJUNCT; = GYROCONIC. | |
| WHORL, DISJUNCT | Having subsequent WHORLS not touching the previous; = DISCONTIGUOUS; = GYROCONIC; see also: LOOSELY COILED. See other gastropod shapes. | |
|
| WHORL, FLATTENED | The condition of having the PERIPHERY of a whorl being flat. | |
| WHORL, HALF | Half of a full turn in the shell spiral of a gastropod; 180 degrees of shell growth. | |
| WHORL, MONOCARINATE | Having a single CARINA on the PERIPHERY of a whorl; see also: WHORL, BICARINATE. | |
| WHORL, ROUNDED | Having a smooth curve on the outer PERIPHERY of a whorl. | |
| WHORL, SHOULDERED | Having an angulation of the whorl at its PERIPHERY or outermost edge. | |
| WHORL, SUCCEEDING | A whorl later in the growth sequence and usually larger than the WHORL in question. | |
| WHORLS, NUMBER OF | The count of revolutions of a shell or of an OPERCULUM. | |