278 TRITON. 



TRILOBATE. (Tp« fi , three ; Xoj3o S , division, lobe.) Divided into 

 three lobes or principal parts. Ex. Malleus, Fig. 165. 



TRILOCULINA. D'Orbigny. A genus of microscopic Foraminifera. 



TRIPARTITE. (Tripartitus) composed of or divided into three 

 separate parts. 



TRIPHORA, or TRISTOMA. Deshayes. A genus composed of 

 small reversed species of Cerithium, Auct. which have the an- 

 terior canal closed at the anterior of the aperture, but opened at 

 the extremity, and a small tubular opening on the upper part of 

 the whorls, making three openings on the body whorl. This 

 genus stands in the same relation to Cerithium as the Typhis to 

 Murex. Fig. 375 in the old plates, and fig. in the new plates. 



TRIPLEX. Humph. Murex, Linn. 



TRIPLODON. Spix. Hyria, Auct. 



TRIPTERA. Quoy et Gaimard, Cuviera, Fer. Described in the 

 Voyage de la Coquille, and represented as a molluscous animal 

 destitute of a shell. 



TRJQUETRA. Bl. Triangular species of Venus Auct. 



TRISIS. Oken. Arca tortuosa, Auct. 



TRISTOMA. Described as Triphora. 



TRITON. Auct. Fam. Siphonostomata, Bl. Canalifera, Lam.— 

 Bescr. Oblong or oval, thick, ribbed or tuberculated, with discon- 

 tinuous varices placed at irregular distances ; spire prominent, 

 mammillated; aperture round or oval, terminating anteriorly in a 

 generally long, slightly raised canal ; columellar lip granulated or 

 denticulated; outer lip thickened, reflected, generally denticulated 

 within ; epidermis rough ; operculum horny. — Obs. However 

 nearly allied the Tritons may appear to be to the Murices and 

 Ranellse there are still to be traced in the shells of each of those 

 genera, several constant and well marked distinctions, by which they 

 maybe at once recognized. In the Ranellee, the varices run in 

 two rows along the spire ; in the Murices, they form three or more 

 rows; but in the Tritons, they do not follow each other, i. e. they 

 do not occur in the same part of each volution. The large species 

 of Triton, are sometimes used as trumpets. The Tritons are 



