from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of, relating to, or located on the right side; right.
- adj. Right-handed.
- adj. Zoology Of or relating to a gastropod shell that coils clockwise and has its aperture to the right when facing the observer with the apex upward.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Of or pertaining to the right side
from the GNU version of the Collaborative International Dictionary of English
- adj. Right, as opposed to sinistral, or left.
from The Century Dictionary and Cyclopedia
- Right, as opposed to left; right-hand.
- In conchology, dextrorse: applied to univalve shells whose aperture is on the right side when the shell is held in front of the observer with the apex upward and the aperture downward toward him: opposed to sinistral. Most shells are dextral.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. of or on the right
- adj. preferring to use right foot or hand or eye
Sorry, no etymologies found.
Check that picture: Ms Saites has an extraordinarily well-developed dextral sternocleido mastoideus.
Such circles always rotate in a clockwise direction, because the genital openings of dextral slugs are on the right sides of their heads.
Therefore, an aberrant individual with a tall sinistral shell among tall-shelled dextral conspecifics is more likely to be able to mate and leave offspring than one with a wide sinistral shell among wide-shelled dextral conspecifics.
The twisting of the head is apparently necessary, because these are both dextral individuals and so, their genital openings are on the right sides of their heads.
Could it still mate with a dextral individual of its own species?
According to the phylogeny of these snakes cited in the paper, the ancestral snakes had symmetric dentition, which suggests that the unequal teeth numbers on the snake's jaws is an adaptation to preying on dextral snails.
In the feeding tests Hoso et al. conducted using dextral and sinistral left-handed individuals of the snail Bradybaena similaris, P. iwasakii required significantly longer handling time with sinistral snails than with dextrals and failed to extract sinistral snails more frequently than dextrals.
Hoso et al. speculate that the wide diversity of sinistral land snails in Southeast Asia may have resulted from selective pressure the snakes have been putting on dextral snails; if dextral snails are more likely to get eaten, then natural selection will naturally select for sinistral variants.
The majority of snail shells are normally dextral the coiling of the shell is right-handed.
In terrestrial pulmonate gastropods the eggs are expelled thru the genital opening, which is located on the right side of the head if the individual is dextral, otherwise, on the left side.