SOLARIUM. Auct. (_A terrace, or gallery_.) _Fam._ Turbinacea, Lam. Goniostomata, Bl.--_Descr._ Discoidal beneath, conical above, with a wide umbilicus, the spiral margin of which is angulated and crenulated; aperture trapezoidal; peritreme thin, sharp; columella straight; operculum horny, subspiral.--_Obs._ The Solarium Perspectivum, is commonly called the Staircase Trochus, from the angulated edges of the whorls being seen through the umbilicus, which reaches to the apex, and presents the appearance of a winding gallery. The species are not numerous, they belong to tropical climates. A few fossil species occur in the tertiary formations. Fig. 353, S. Perspectivum. SOLDANIA. D'Orb. A genus of microscopic Foraminifera. SOLEN. Auct. (_A kind of shell-fish_, Plin.) _Fam._ Solenacea, Lam. Pyloridea, Bl.--_Descr._ Bivalve, transversely elongated, sub-cylindrical, equivalve, very inequilateral, gaping at both extremities, umbones terminal, close to the anterior extremity; hinge linear, with several small cardinal teeth, and a long, external ligament; muscular impressions distant, anterior tongue-shaped, placed behind the cardinal teeth, posterior irregular, sub-ovate; palleal impression long, bilobed posteriorly.--_Obs._ The above description of the genus Solen, is framed so as to admit only those species which are commonly called Razor Shells, with the umbones terminal, and the anterior muscular impression behind them. They are found buried deep in the sand, in a perpendicular position, their situation being pointed out by a dimple, on the surface. They are abundant in temperate climates. Some of the Lamarckian Solenes will be found in the genus Solenocurtus, Bl. Fig. 60, 61. SOLENACEA. Lam. A family of the order Conchifera, Dimyaria Lam. The shells belonging to it are described as transversely elongated, destitute of accessary pieces, gaping only at the lateral extremities; ligament external.--The genera may be thus distinguished. 1. SOLEN. Razor shells, truncated at the extremities. Fig. 60. 2. PANOPÆA. Broad, with prominent tooth. Fig. 65, 66. 3. SOLENOCURTUS. Rounded at the extremities, with internal bar. Fig. 61. 4. SOLENIMYA. No teeth, epidermis over-reaching the shell. Fig. 68. 5. GLYCIMERIS. Thick, fulcrum of the ligament prominent. Fig. 67. 6. LEPTON. Flat, scale-shaped. Fig 62. 7. NOVACULINA. Umbones nearly central; covered by a thin epidermis. Fig. 63. 8. GLAUCONOME. Oval, margins close. Fig. 64.