352 PROCEEDINGS OF THE ACADEMY OF a unifoliolate bract. Calyx-teeth much longer than the tube, almost equal-ling than the corolla. Leaves subsessile, pinnately trifoliolate or the upper sometimes unifoliolate. (Psychopsis, Nutt. in Torr. and Gray, Fl. 26. Hosackia Purshiana, Benth. in Bot. Reg. Lotus sericeus, Pursh. Trigonella Americana, Nutt. Gen. Hosackia unifoliolai a, Hook. H. elata, flo-ribunda, pilaw, and mollis, Nutt. in Torr. and Gray, Fl. A wide-spread and variable species, from a few inches to a foot or more high, smoothish, or even glabrous, pubescent, or soft-villous ; the leaflets varying from ovate to lan-ceolate. North Carolina to Nebraska, Oregon, and California. ft Flowers subsessile and mostly solitary in the axils of the leaves, ebracteate. Corolla exceeding the calyx. Leaves 3 5-foliolate ; the leaflets obovate or oblong, mostly attenuate or scattered on the wing-dilated rhachis. Small, procumbent or depressed annuals. 27. H. rubpinnata, Torr. and Gray, Fl. Lotus subpinnatus, Lag. ; Hook, and Arn. Bot. Beech, t. 8. L. Macrcei, Benth., forma subglabra. L. Wran-gelianus, Fisch. and Mey. H. Wrangpliana, Torr. and Gray, I. c, forma glabrata. Villous-hirsute or glabrate. Teeth of the calyx about the length oi the tube, or scarcely longer. Legume linear-oblong, 4 7-seeded, as in forego-ing species, very much exceeding the calyx. The smoothish variety, with a glabrous legume (Lotus Macrozi, Benth.), appears different enough from the very hairy form, which is less common in California. But intermediate states abound. Anisolotus anthylloides, Bernh., of the gardens, appears to be a slender and procumbent form. Chili, California, and Oregon. 28. H. brachycakpa, Benth. PI. Hartw. p. 306, No. 1073. Softly villous with long and whitish hairs, very much branched from the base, diffuse or procumbent ; the flowers rather larger than in the last ; the attenuated teeth of the calyx very much longer than its tube, and equalling or fully half the length of the oblong or linear-oblong very obtuse villous 2 4-seeded legume. California, on the Sacramento, and in that region. Dr. Brewer has collected greener and luxuriant specimens of this species, approaching 11. subpinnata, having flattish pods which exceed the calyx ; but the species still appears to hold good. *** Obscure Species. H. balsamifera, Kellogg, in Proceed. Calif. Acad. ii. p. 125, said to be very viscid and villous, and to have pedunculate umbels, is wholly unknown to me. Synopsis of the ECHINOIDS collected by Dr. W. Stimpson on the North Pacific Exploring Expedition, under the command of Captains Ringgold and Rodgers. BY ALEX. AGASSIZ. The cqllection of Echinoids brought home by Dr. Stimpson was at first placed in the hands of Mr. James M. Barnard for identification. Other occu-pations having prevented him from finishing the task he had undertaken, the collection was sent to Cambridge, where it was arranged while I was engaged in cataloguing the Echinoids of the Museum of Comparative Zoology. The specimens have thus been compared with the greater part of the originals of the Catalogue Raisonne" of Prof. Agassiz, which are in the collection at Cam-bridge. Dr. Stimpson has collected so largely that the species which had not been described before, and which are here briefly noticed, form a large addition to the number of Echinoids previously known to science. He has visited several of the localities from which the French explorers had brought to the Jardin des Plantes many of the species mentioned in the Catalogue Rai-[Dec.