shell coilingの例文

• Note that Pilsbry described the shell as if it were dextral, whereas planorbids are now known to be sinistral in shell coiling.
• Like other vermetids, the species in this genus do not have regular shell coiling like that of a typical gastropod shell, instead they have shells which are irregular.
• Although it is now understood that these species are sinistral in shell coiling, disk-like Planorbid shells are often still shown in illustrations oriented as if they were dextral.
• The rest of the species in the genus are right-handed or " dextral " in the shell coiling, as is usually the case in the great majority of gastropods.
• This globular shape, tight shell coiling, strong sculpture, a dentate outer lip and narrow aperture offers an added protection against shell-crushing predators, such as fishes and crabs.
• In its religious context, the " Dakshinavarti shankh " is considered to be right-handed, because the " handedness " of the shell coiling is measured with the " spout " or siphonal canal of the shell pointing upwards.
• All coiled shell Planorbidae are sinistral in their shell coiling, as is proved by their internal anatomy ( the respiratory and the genital orifice are situated on the left side ), however the animals carry their shells with what would normally be the ventral ( i . e . umbilical ) surface uppermost, and because of this, the shells appear to be dextral.