This species has a tall, erect and slender stem reaching about forty or fifty feet in height and armed with numerous, long, conical, woody spines arranged in rings. The leaves are rather small with the leaflets rigid and very slightly drooping at the tips, and united at the base for about one-eighth of their length. The petioles are long and slender and are deciduous, the entire leaf falling away from the stem. The midrib and edges of the leaflets are armed with weak spinules. The spadices are small and grow somewhat erect so as to be partly concealed among the leaves, and the fruit is oval and rather small. This species grows on the Upper Rio Negro and Atabapo, in marshes, with a rocky subsoil, and in the moist parts of the Catinga forest. The Caraná, common in the swamps (not in the tide-flooded lands) about Pará, is very closely allied or may be the same species. [Illustration: Pl. XX. W. Fitch. lith. Ford & West Imp. MAURITIA GRACILIS. Ht. 30 Ft. ] PLATE XX. MAURITIA GRACILIS, n. sp. Caranaí, _Lingoa Geral_. This very elegant species is rather smaller than the last. The stem is from twenty to thirty feet high, slender, waving, and ringed with conical spines rather smaller than in _M. aculeata_. The leaves are from five to eight in number with much-drooping leaflets. The petioles are slender, short, and greatly dilated at the base. The spadices are three or four in number, growing from among the leaves, of very large size in proportion to the tree, much branched and drooping. They bear great quantities of fruit, which is of an oval shape and nearly as large as that of the _Mauritia carana_. This beautiful little palm is first met with about Barcellos on the Rio Negro, more than 300 miles up the river, and is thence common as far as the black-water tributaries of the Orinoco. It always grows close to the water’s edge in clumps of thirty or forty individuals, and its drooping leaves of a pale hoary green colour, never so much crowded as to lose their distinct outline, with the bending clusters of rich brown fruit, render it one of the greatest ornaments of its native river. The fruit is eaten, after being softened by soaking some time in water. It seems closely allied to _M. armata_ of Martius, which is found much farther south, on the banks of the S. Francisco River, but is probably quite a distinct species. [Illustration: Pl. XXI. W. Fitch. lith. Ford & West Imp. MAURITIA PUMILA. Ht. 10 Ft. ] PLATE XXI. MAURITIA PUMILA, n. sp. Caranaí, _Lingoa Geral_.