V. Observations on the post-embryonic development of Ciona intestinalis and Clavelina lepadiformis

The following is an account of some of the observations which were made by the author during an occupation of the British Association Table at the Zoological Station at Naples from October, 1891, to May, 1892. In their admirable “Recherches sur la Morphologie des Tuniciers,” (‘Archives de Biologie,’ vol. 6, 1887), Édouard van Beneden and Charles Julin came to a num ber of conclusions which, while they appeared to follow naturally from the facts observed, yet only added, if possible, to the perplexity surrounding any attempt to regard the Ascidians andAmphioxus from a common standpoint.