Microspines in the alimentary canal of Arthropoda, Onychophora, Annelida

The presence and Variation of microspines within the foregut and hindgut of the taxa Arthropoda; Onycophora, and Annelida were presented. Microspines appear to be sympleisiomorphic to the Arthropoda sensu stricto. Unispinose microspines constitute the original ancestral condition, and these have bee n retained and variously modified within the classes to aid in filtering in gested food, food movement through the gut and retain symbionts, and possib ly protect the cellular linings of the gut in particulate food eaters. (C) 1998 Elsevier Science Ltd. All rights reserved.