Ovate-globose, 2.5 to 3 cm. in diameter, 2.5 to 6 cm. high, proliferous and at length cespitose: tubercles 7 to 9 mm. long, the long axillary wool intermixed with several coarse twisted bristles: radial spines very numerous, in many series, the outer ones (30 to 50) capillary, white, elongated and flexuous or crisped (12 to 16 mm, long when straightened), the inner ones (10 to 12) more rigid, shorter (6 to 8 mm.), puberulent, whitish or yellowish, usually dark-tipped; central spines 5 to 8, rigid, straight, pubescent, unequal, white below and reddish or dark above: flowers 1.5 to 2 cm. long, the yellowish-white petals with reddish median band: fruit 1.5 to 2 cm. long: seeds black and shining, conspicuously pitted, 1.2 mm. long. (Ill. Cact. Mex. Bound. t 5.) Type, Bigelow specimens in Herb. Mo. Bot. Gard. From the mouth of the Rio Grande to El Paso, Tex., and southward into Coahuila and Chihuahua. Fl. March-May. Specimens examined: Texas (Bigelow of 1853; Nealley of 1892): Coahuila (Bigelow of 1853): also growing in Mo. Bot. Gard. 1892 and 1893. The exterior capillary spines cover the whole plant as with a coarse wool. 32. Cactus pringlei, sp. nov. Globose (?), 5 cm. in diameter: tubercles short-conical, about 6 mm. long, with very woolly axils: radial spines 18 to 20, setaceous-bristly and radiant, 5 to 8 m in. long; central spines 5 to 7 (usually 6), stout and horny, more or less recurved, spreading, 20 to 25 mm. long; all straw-colored, but the centrals darker: flowers deep red (darker, even brownish, outside), 8 to 10 mm. long: fruit unknown. Type, Pringle of 1891 in Herb. Gray. San Luis Potosi. Specimens examined: San Luis Potosi (Pringle of 1891). Evidently a member of the Chrysacantha group and near C. rhodanthus sulphureospinus, but differs in the much shorter tubercles, straw-colored spines, shorter radials, much longer centrals, and smaller darker flowers. 33. Cactus sphaerotrichus (Lem.) Kuntze, Rev. Gen. Pl. 261 (1891). Mamillaria sphaerotricha Lem. Cact. 33 (1839). Depressed-globose: tubercles cylindrical, obtuse, with some axillary bristles: radial spines very much crowded, exceedingly numerous, radiant, very slender and bristle-like, white; central spines 6 to 10 and even more, erect and more rigid: flowers pale reddish: fruit unknown. Type unknown. Referred to Mexico in general, but reported only from San Luis Potosi. Specimens examined: Mexican specimens from Hort. Dyck in 1857; from Hort. Pfersdorff in 1869; and growing in Mo. Bot. Gard. 1893 (from material sent by Pringle from San Luis Potosi). ++ The single central spine shorter than the radials (in C. longimamma centrals often more than one and somewhat longer). 34. Cactus gabbli, sp. nov. Mamillaria gabbii Engelm Mss.