BACI LLA'R I A, a large family of I nfusorial Animalcules, constituted by Ehrenberg, who includes in it upwards.of 30 genera. The ailicious shields of these animalcules are amongst the most numerous of the forms of Micro:eerie in the Cretaceous, Tertiary, and Superficial Deposits. Xanihidia occur in the Chalk and its included nodules of flint : Csi Nariculm, itetinocycli, Coscinodiaci, Gomphonemte, and other genera, abound in the white Tertiary Maria of Greece, Italy, Bohemia, England, and North America. The Silicions Beds of Bohemia (Polierschiefer), which are 14 feet in thickness, contain innumerable shields of Nariculte, and probably few of the superficial lacustrine deposits of Europe are wholly devoid of these couvite. [DreemACEE•] BA'CTRIS, a genus of Palms, consisting of a considerable number of species, found about rivers and in marshy places in America within the tropics, especially near the Line. Their trunk is usually of moderato height, or even dwarfish, never exceeding 20 feet ; sometimes having the stout tree-like aspect of palms in general, but often more resembling reeds. They often grow in dense patches, forming impassable thickets, on account of the numerous, long, hard, black spines with which the stem is protected. The wood is generally
hard and black towards the outside, but pale yellow internally, with black fibres. The leaves usually grow all over the surface of the stem, instead of being confined to the summit only. They have extremely spiny stalks, and are either pinnate(' after the manner of the date-palm, or merely consist of two broad, sharp, diverging, plaited lobes. The fruit is small, soft, with a subacid rather fibrous pulp inclosed in a bluish-black rind, and affords a grateful fruit to small birds. • Bnetria acenthocarpa, a species which grows 12 or 15 feet high in the primaeval woods about Bahia, forming patches 30 feet in circum ference, and having elegant pinnate(' leaves 6 or 8 feet long, with stout spines on their stalks, yields an extremely tough thread, from which the natives, who call it Tueum, manufacture strong nets. Its drupes are of a kind of vermilion-red, bristling with short black prickles.
Martins mentions 17 other species.