Defn: Of or pertaining to the rhachis; as, the rhachidian teeth of a mollusk.
RHACHIGLOSSA
Rhach`i*glos"sa, n.pl. Etym: [NL. See Rhachis, and Glossa.] (Zoöl.)
Defn: A division of marine gastropods having a retractile proboscis and three longitudinal rows of teeth on the radula. It includes many of the large ornamental shells, as the miters, murices, olives, purpuras, volutes, and whelks. See Illust. in Append.
RHACHILLA
Rha*chil"la, n. Etym: [NL., fr. Gr. "ra`chis the spine.] (Bot.)
Defn: A branch of inflorescence; the zigzag axis on which the florets are arranged in the spikelets of grasses.
RHACHIODONT
Rha"chi*o*dont, a. Etym: [Gr. "ra`chis, -ios, the spine + (Zoöl.)
Defn: Having gular teeth formed by a peculiar modification of the inferior spines of some of the vertebræ, as certain South African snakes (Dasypelits) which swallow birds' eggs and use these gular teeth to crush them.
RHACHIS
Rha"chis, n.; pl. E. Rhachises, L. Rhachides. Etym: [See Rachis.]
[Written also rechis.]
1. (Anat.)
Defn: The spine.