Page:A Voyage of Discovery and Research in the Southern and Antarctic Regions Vol 1.djvu/435

Rh much resembling the Hornera frondiculata of Lamouroux in similar fresh condition. The polype cells are salient only at the extremities of the branches. The cells appear also on all sides of the branches, which must distinguish it from the species mentioned. The absence of the openings of polype cells from the exterior side of the branches is made a generic character of Hornera by Lamouroux, but probably is only of value to distinguish species.

I name this Hornera lateralis.—The genus Hornera was established by Lamouroux for a division of Retepora, of which R. frondiculata is the type, but it was not well defined by him. The generic character, as given by Milne Edwards, is, 'Polyparium branched, composed of tubular cells united together throughout nearly their whole length, with terminal circular openings. The cells all opening on one surface.'

The cells of the present species are not so decidedly elongated as those of H. frondiculata, and it may be said to occupy an intermediate place between Hornera and Retepora, but this is one of the ordinary difficulties in arranging species in genera. An instance of such difficulty is seen in the species R. versipalma, which Lamouroux says (Expos. Method, p. 41.), 'est tres voisin des Hornères,' which De Blainville places in the genus Hornera, and of which Milne Edwards says, (Anim. sans Vertèbres, Second Edition, vol. ii. p. 279.) 'Nous sommes porté a croire que ce Polype ne doit pas être rangé dans le genre Hornère, ainsi que le veut M. de Blainville; il nous parait se rapprocher davantage des vrais Retepores."

"The present species differs from all that are described in the opening of the cell which, as is shown in fig. 3, is placed laterally immediately below the pointed summit of the cell. It is only at the unbroken ends of the branches that this can be seen, as the ends of the cells seem soon to