The ascidian Clavelina cylindrica, which was collected in Tasmania, has yielded two novel alkaloids, cylindricine A, rel-(3R,4R,5S,7aR,11aR)-3-chloromethyl-5-hexyl-perhydro-pyrrolo-[2,1-j]quinolin-7-one, (12), and cylindricine B. rel-(3S,5R,6S,8aR,12aR)-3-chloro-6-hexyl-perhydropyrido[2,1-j]quinoline-8-one, (13). Cylindricine B is the first example of the new pyrido-[2,1-j]-quinoline ring system while cylindricine A is the first pyrrolo[2,1-j]quinoline known from nature. Single crystal X-ray studies support the assignment of the two alkaloids.