Specimens examined: Lower California (W. M. Gabb 17 of 1867, near Loreto; Brandegee of 1889, at San Gregorio; Palmer 139 of 1890, near La Paz; Palmer 880 of 1890, on Carmen Island; Brandegee 241 of 1890, at Rancho Colorado). One of the most showy species of Lower California. The plant has the appearance of a Coryphanth, and is remarkable for its tall and slender habit, its large central hooks, and its globose fruit. Since 1867 this species has been in Herb. Engelmann, fully characterized as above under the very appropriate specific name longihamatus. 24. Cactus setispinus, sp. nov. Mamillaria Setispina Engelm. Mss. Fasciculate and ascending, simple or branched at base, the stems about 30 cm. high and 3 to 6 cm. in diameter, densely covered with remarkably long stout spines: tubercles short and broadly conical, with axillary wool: spines white. with black tips; radials 10 to 12, widely spreading, very unequal, 10 to 34 mm. long, slender and flexuous; central spines 1 to 4, more rigid and much longer (20 to 50 mm.), the upper ones straight, the lowest one longest and hooked (usually upwards) and often variously curved and twisted: fruit obovate and scarlet 30 mm. long: seeds, black and pitted. Type, Gabb 15 in Herb. Mo. Bot. Gard. Rocky or gravelly soil, San Julio Canyon. and in the vicinity of San Borgia, Lower California. Specimens examined: Lower California (W. M. Gabb 15 of 1867, at San Borgia; Brandegee of 1889, from San Borgia and San Julio Canyon). In his notes Mr. Gabb describes the flower as "large, 3 to 3.5 inches long, bell-shaped, of a beautiful purplish red color," concerning which Dr. Engelmann remarks "this would indicate a Coryphanth, but the tubercles show no trace of a groove, and, moreover, a withered remnant of a flower laterally attached (say 18 to 20 mm. long), so that I have no doubt that Mr. Gabb's statement is founded on some error." It is very probable that the flowers are scarlet and larger than Dr. Engelmann suggests. The species is closely allied to C. roseanus, but differs in its shorter tubercles and much longer spines. About a dozen stems rise in a clump, about a foot high, covering an area of 2 or 3 feet. These two species represent a very distinct Lower Californian group of cylindrical and hooked Eumamillarias. Both probably have showy scarlet flowers and may attain considerable length when growing upon rock ledges so as to become pendent. The specimens of C. setispinus from San Julio Canyon are from younger parts and show but a single long and hooked central. The San Borgia specimens show mostly 3 or 4 centrals, the lowest one hooked and becoming remarkably long and often variously twisted and curved. However, I can discover no difference except such as may be due to age. ++ Central spines present and not hooked. + Central spines more than one, longer than the radials, which are numerous, white and slender (capillary or bristle-like) (rigid in C. Halei).