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Show 142 PROF. F. J. BELL ON ECHINODERMATA [Feb. 15, separates them from the poriferous area ; this last extends down to the edge of the actinal surface. On the abactinal surface there are scattered tubercles and large poriferous patches ; over the whole there is a uniform granulation ; no pedicellarise were detected. The madreporic tubercle is large and prominent. Colour, in spirit, light yellow, the poriferous patches darker. Measurement round the equator 560 mm.; height 75 m m . along the longest axis. The most interesting points with regard to this species are such as bear on its relation to the Echinoidea. Those who accept the old doctrine of Cuvier and Duvernoy, restored in these days by Prof. Haeckel, which explains the constitution of the Echinoderm by the hypothesis that it consists of several fused persons, have found in Culcita the form that seemed to show how the free arms of the Starfish might pass into the compact form of the Urchin. This theory of Echinoderm constitution does not recommend itself to m e ; and the present species seems to justify the hesitation which one feels in accepting it. While in flattened or irregular Echinoids there is a tendency for the ambulacra to shorten towards the aboral pole, here the tendency is for the shortening to be towards the mouth. In other words, the most extreme Asterid which we know, though it has a remarkable general resemblance to an Echinoid, is, in its essential morphological points, further from it than is a typical Asterid. CULCITA GREX. With a little hesitation I refer a single specimen to this species ; the variability of the forms of the genus Culcita is obviously very great, and a careful revision of the species with the aid of a large number of specimens is a pressing necessity. The collection in the National Museum is not yet sufficiently large to justify me in undertaking the task. CULCITA, sp. There are two specimens of what would, a short time ago, have been set down as Randasia granulata. As, however, M . de Loriol has lately shown, the form so called by the late Dr. Gray is really a young stage of Culcita. It will be remembered that Prof. Perrier has expressed himself in a similar sense. Further series are required before the several stages of each species can be accurately defined. ECHINOIDEA. DlADEMA SETOSUM. I am really very doubtful as to the specific identity of two small specimens, the spines of which are banded light and dark, and present the characters of Dr. Gray's "•Calmariusannellata," with the adult large hlack-spined forms which are assumed by D. setosum. However, I have not sufficient evidence to justify m e in attempting to refute the |