SOLENELLA. Sow. (_Solen._) _Fam._ Arcacea, Lam.--_Descr._ Oval, equivalve, subequilateral, compressed, covered with a thin, shining, olive-green epidermis; hinge with three or four anterior, and numerous sharp posterior lateral teeth, arranged in a straight line; muscular impressions two, lateral; palleal impression with a large sinus; ligament external, prominent, elongated.--_Obs._ This genus partakes of the characters of the genus Nucula, and of the family Solenacea. A few specimens of the only species known (S. Norrisii, fig. 138.) were dredged by Mr. Cuming at Valparaiso. SOLENIMYA. Lam. (Solen and Mya.) _Fam._ Mactracea, Lau. Pyloridea, Bl.--_Descr._ Equivalve, inequilateral, transversely oblong, rounded at the extremities with the umbones near the posterior side, covered with a shining brown epidermis extending beyond the edges of the shell; hinge without teeth; ligament partly internal, placed in the margin of an oblique, flattish, posterior rib; muscular impressions two, distant, lateral. From the Mediterranean, Australian, and Atlantic Oceans.--_Obs._ Solenimya differs from Solenocurtus and the true Solens, in having the posterior side of the shell the shortest; in the internal ligament; and in being destitute of teeth. It resembles Glycimeris, but is not incrassated. Fig. 68, Solenimya radiata. SOLENOCURTUS. Bl. (_Solen_ and _curtus_, short.) _Fam._ Pyloridea, Bl. Solenacea, Lam.--_Descr._ Oval, elongated, equivalve, sub-equilateral, with the edges nearly straight and parallel, and the extremities rather truncated; umbones not very prominent, sub-central; hinge with or without two or three rudimentary cardinal teeth; ligament prominent, placed upon thick callosities; muscular impressions two, distant, rounded; palleal impression straight, with a deep sinus. East Indies--_Obs._ Distinguished from the true Solenes by the central position of the umbones and an internal bar reaching partly across the shell. SOLETELLINA. Bl. SANGUINOLARIA radiata. S. Diphos, f. 99. S. livida of Sowerby, and similar species, are placed together in this genus. SPATHA. Lea. A sub-genus of IRIDINÆ, consisting of I. rubens and I. nilotica, which have not distinctly crenulated margins. Spatha solenoides, of Lea, is the genus Mycetopus D'Orbigny. Fig. 151. SPHÆNIA. Turt. A genus consisting of a small species resembling Saxicava, in general appearance, but having a spoon-shaped process on the hinge of one valve. S. Binghamii, Fig. 96. SPHÆROIDINA. D'Orb. A genus of microscopic Foraminifera. SPHÆRULACEA. Bl. The first family of Cellulacea consisting of the following genera of microscopic Foraminifera: Miliola, Melonia, Saracenaria, Textularia.