Ap-pen´dix ver-mi-for´mis [Lat. appendo, to hang from; vermis, worm; forma, form.] A vestigial structure attached to commencement of the large intestine.
A-rach´ni-da [Gr. arachne, spider.] A class of Arthropods embracing the spiders, mites, scorpions, etc.
Ar-cel´la [Lat. dim. arca, a box.] Belonging to a group of protozoans having a chitinous shell.
Ar-chæ´an [Gr. archaios, ancient.] Pertaining to the oldest strata of rocks in geological history.
Ar-chæ-op´ter-yx [Gr. archaios, ancient; pteryx, bird.] A fossil bird with reptilian characteristics.
Ar-che-go-sau´rus [Gr. archegos, beginning; sauros, lizard.] A carboniferous amphibian (labyrinthodont.)
Ar´go-naut [Gr. argo, swift; nautes, sailor.]
Ar-ma-dil´los [Sp. dim. of armado, armed.] Edentate mammals having a carapace formed by ossification of the greater part of the skin and the union of the bony scutes.
Ar-throp´o-da [Gr. arthron, joint; pous, foot.] A branch of animals (invertebrates) with jointed legs, as insects, spiders, and crabs.