This is especially the case in the anterior part of the body, where, in correlation with the adaptational shifting of the oral aperture (see Arthropoda), a varying number of somites unite to form the cephalon or head.
- It appears (see Arthropoda) that there is embryological evidence of the existence of two somites in Arachnida which were originally post-oral, but have become prae-oral by adaptational shifting of the oral aperture.
adaptational הגייה עם משמעויות, מילים נרדפות, הפכים, תרגומים, משפטים ועוד