92 Miscellaneous. and a Ctcuophore (pi. iii. fig. 25) with its lateral tubes on the sides of the digestive cavity (_</), leading into the chymifcrous pouches («'), branching into the chyniilcrous tube. The coeliac openings (pi. iii. fig. 4.5, rn) of the funnel he looks upon as repre-senting the raadrcporic body, Avhile I look upon them as the anal openings. In this view of the case, the Clenophore is rather more in the embryonic condition of the Ecliinoderni larva, when the actinostome leading into the digestive cavity should perform at the same time the function of mouth and anus, whidi it occasionally does, although at other times tlie coeliac ojjcning of the funnel seems to be the true anal opening, while, according to Metschiiikoff, it is the madreporic body which perfurms the part of an anal opening. He says it only acts to introduce water into the system, which is contrary to my observations. I may here recall former statements* concerning the affinities of the Ctenophora, when describing some of the younger stages. It could only be after a careful comparison of Ctenophorous and Echinoderm embryos that undoubted evidence of their identity of plan might be obtained. The Ctenophora retain the permanently embryonic features of Echinoderm embryos, in which the water-system is still connected with the digestive cavity. The formation of a funnel as a sort of alimentary canal, opening externally through the coeliac apertures at the abactinal pole, corresponds to the exist-ence of a short alimentary canal in Echinoderm larva). The Cteno-phora are, from their embryology, more closely related to the Echino-derms than to the other Acalephs ; and it seems natural to separate the Acalephs into two orders — the Ctenophora, characterized by the presence of locomotive flappers, and the Medusida), including the Discophora and Hydroids. — From the Memoirs of the American Academy of Arts and Sciences, vol. x. no. iii., August 1874. Notice of Papers on Embryology by A. Kotvalevshy. By A. Agassiz, A. Kowalevsky has published, unfortunately in Kussian, two capital papers on embryology. The one continues the investigations he had been carrying on regarding the existence of an ectoderm and entoderm layer in the early embryonic stages of Invertebrates. In the present paper he has given a sumniary of the early stages of a Cam/)rt?u</orjrt, confirming the observations of Wright and A. Agassiz. For lihizostoma and Cassiopea he shows that the digestive cavity is formed by the invagination of the ectoderm. This is contrary to the results of previous observers, except ISchneider. Eor I'eJagia he shows a direct development from the v'^\i remarkably similar to that of the Gcryonidoe as we know it from Htickel, Fol, and Metsch-iiikoff. He adds nothing to the embryolog}' of Actinia not already known from the magnificent monograph of Lacaze-Duthiers. He then passes on to the development of Ahyoniuin, of which he gives an extremely interesting sketch supplemented by fragments on the embryology oi Astrcea, Goryonia, and Cerianthus : the deve-lopment of the latter is strikingly .similar to that of Edivardsia, as we know it during its passage from Arachnactis to Edwardsia. He * Alexander Agasf-lz. 111. Cat. M. C.Z. n... 1', p. li>, 1865.
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