This is a tall and elegant species. The stem is from fifteen to twenty feet high and about one inch in diameter, with a few scattered groups of small spines. The leaves are regularly pinnate, with broad leaflets narrowed at the base and ending in a lengthened point, the terminal pair being rather broader. The petioles and their sheathing bases are covered with broad, flat, whitish spines. The spadices grow from among the lower leaves on long stalks and are simply branched and drooping. The spathes are elongate fusiform and spiny, and are persistent. The fruit is small and globular. This very graceful palm grows in the moist part of the virgin forest of the Upper Rio Negro, where I found it on the banks of small forest streams; and it seems quite distinct from any of the very numerous species described by Martius. [Illustration: Pl. XXXI. W. Fitch lith. Ford & West Imp. BACTRIS —— Ht. 20 Ft. ] PLATE XXXI. BACTRIS ——, n. sp. Native name unknown. The stem of this curious palm is from twenty to twenty-five feet high and very slender. It is marked with slightly sunk rings and has a few scattered spines. The leaves are rather small, few in number and terminal. The leaflets are rigid, narrowed at the base, widest near the end and suddenly tapering to a point. They are arranged in groups of three or four at short intervals along the midrib, from which they stand out at different angles. The petioles and their sheathing bases are thickly set with slender, flattish, black spines generally pointing downwards. This species was only found once, growing in the “gapó” or flooded lands of the Upper Rio Negro, and at the time had neither flowers nor fruit. The form and arrangement of the leaflets are so peculiar that it cannot be confounded with any species yet described. A leaflet is represented of a larger size to show the peculiar form. [Illustration: Pl. XXXII. W. Fitch lith. Ford & West Imp. BACTRIS MACROCARPA. Ht. 10 Ft. ] PLATE XXXII. BACTRIS MACROCARPA, n. sp. Iú, _Lingoa Geral_. This species has the stem about an inch in diameter and ten or twelve feet high, distinctly jointed, smooth and reed-like, but with a few spines in small groups at the joints. The leaves are terminal, of moderate size and rather interruptedly pinnate. The leaflets often grow in pairs and are broad, narrowed at the base and have the midrib produced at the point, the terminal pair being the largest. The petioles and sheaths are thickly set with whitish flat prickles. The spadices are small, five- or six-branched, and rather long-stalked. The spathe is small, smooth and persistent. The fruit is oval, with a produced apex, large in proportion to the tree, of a reddish or yellowish olive colour, and not eatable, the outer covering being dry and woolly.