Base Z (Part I, J., 1937, 1821), C12H21O 2N, is a mixture of about 10 parts of poroidine (isovalerylnortropëine) with 1 part of isoporoidine (d-α- methylbutyryl-nortropëine), and has been indirectly racemised. The former constituent was separated by an indirect method, and both have been synthesised; their mixture in the above ratio was shown to be similar to base Z. A probable derivation of these bases from leucine and isoleucine respectively is suggested. Tiglylnortropëine, tiglyltropëine (Part I, loc. cit.), and dl-α-methylbutyryltropëine have also been prepared. The hydrobromides of all the alkaloids mentioned are freely soluble in chloroform. The p-phenylphenacyl esters of the butyric and valeric acids are described. A method for recovery of acid and alcohol from such esters is also given.