From the root bark of the West Indian tree Rauwolfia- tetraphylla L. there have been isolated the following alkaloids: re-serpine, ajmaline, serpentinine, Ψ-yohimbine, tetraphylline and tetraphyllicine. The last two alkaloids are new and evidence is presented for the structure assignment of these substances. Tetraphylline (I) is a stereoisomer of reserpinine and isoreserpinine and must differ from these two members of the ajmalicine group in the configuration of one or more of three centers (positions 15, 19 and 20) since destruction of the asymmetric center at C-3 does not yield identical derivatives. The structure of tetraphyllicine (X) follows from its conversion to desoxyajmaline upon hydrogenation and the isolation of acet-aldehyde by ozonolysis, and it represents an interesting biogenetic intermediate in this class of alkaloids. Tetraphyllicine is identical with the hydrolysis product of rauvomitine thus proving the latter's constitution as tetraphyllicine trimethoxy-bcnzoate (XI). A possible structure for ajmalidinc (XII), an alkaloid isolated in trace amounts from R. selhtvii, is presented. Some observations on serpentinine are also recorded in the Experimental portion of this paper. © 1957, American Chemical Society. All rights reserved.