Sinistral and dextral

Sinistral and dextral, in some scientific fields, are the two types of chirality ("handedness") or relative direction.

Other disciplines use different terms (such as dextro- and laevo-rotary in chemistry, or clockwise and anticlockwise in physics) or simply use left and right (as in anatomy).

A small minority of species and genera have shells in which the coils are almost always sinistral (left-handed).

[2] The most obvious characteristic of flatfish, other than their flatness, is their asymmetric morphology: both eyes are on the same side of the head in the adult fish.

Primitive spiny turbots include equal numbers of right- and left-sided individuals, and are generally more symmetric than other families.

Left: The normally sinistral (left-handed) shell of Neptunea angulata , a species of sea snail (now extinct) found mainly in the Northern Hemisphere.
Right: The normally dextral (right-handed) shell of Neptunea despecta , a similar species found mainly in the Southern Hemisphere.
European flounder , like other flatfish , experience an eye migration during their lifetime, making them asymmetric.
Schematic illustration of the two strike-slip fault types. The view is of the Earth's surface from above.