trigon i a

[Mod. Lat.) (TRIGON.] 1. Bot.: The single genus of the order Trigoniaceae, Tropical American trees with opposite, stipulate leaves, their inflorescence in panicles, irregular flowers, and long, hairy seeds. Shell entirely 2. Zool. & Palæont .: The sole recent genus of Trigoniade (q. v.), with three species (or varieties) thick, tuberculated, or ornamented with radiating or concentric ribs; posterior side angular; ligament small and prominent; hinge-teeth 2-3, diverging. Animal with a long, pointed foot, bent sharply, heel prominent; gills ample, the outer smaller than the inner, united behind the body to each other and to the mantle. The species are very active. They are probably migratory, as in dredg ing for them it is very uncertain where they may be obtained. A hundred fo il species are known, widely distributed in space, and ranging in time from the Lias to the Chalk, but almost, if not entirely absent from the Tertiary. The shell is wanting or metamorphic in Limestone strata. trigon i a-grits, s. pl. Geol.: Two grits, an upper and a lower, characterized by the presence of species of Trigon i a. *tri-go-ni-ā-çě-æ, s . pl . [Mod. Lat.trigon i (a); Lat. fem. pl.adj. suff. - aceœ.] Bot.: Von Martius' name for an order which he separates from Polygalaceae (q. v.), on account of its opposite leaves, the po e ion of stipules, . trig-o-ni-a-dæ, tri-gon-i-daæ, s. pl . [Mod. Lat. trigon i a ; Lat. fem. pl. adj. suff. -( i )dæ.] 1. Zoology : A family of Conchiferous Mollusks, group Integro-pallial i a. Shell equivalve, close, trig onal, umbones directed posteriorly; ligament external, interior nacreous; s; hinge-teeth few, diverging; pallial line simple. Animal with the mantle open; foot long and bent; gills two on each side, recumbent; palpi simple. (TRIGON I A.] 2. Palæont.: Five fo il genera, ranging from the Lower Silurian to the Trias. tri-gon-1-de, s. pl. [TRIGONIADE.] trig-on-o-, pref. [TRIGON.] Triangular; having a triangular proce or proce es. karpos fruit.]