outer are oval in outline; some are faintly conjugate, and others not so: the extension of the outer rows of pores beyond the petals and towards the ambitus is scanty. The anal furrow reaches nearly to the vertex; and the opening is triangular in outline, the upper angle being slightly rounded, whilst the base is below the level of the ambitus, with which it does not interfere. The ambitus is rounded, and the actinal surface is concave from side to side, and from before backwards, the slope being towards the actinosome, which is small, eccentric in front, transverse and elliptical in outline, the posterior lip being rather straight and on a level with the anterior. The floscelles are small. The tuberculation is small everywhere, and smallest in the anal groove.
Height of specimen 410 inch, length 1210 inch, breadth 910 inch.
Locality.—No. 5, Upper Coralline Beds, Cape Otway.
Pygorhynchus Vassali, Wright.
A very perfect small specimen was found east of the Glenelg river, in a matrix of white limestone crowded with Polyzoa. It resembles in its shape and details that figured by Dr. Wright, F.G.S., &c. in Quart. Journ. Geol. Soc. vol. xx. pl. xxii. fig. 6; and he considers the Maltese form there delineated to belong to the genus Pygorhynchus. In the Australian and also in the Maltese specimen the periproct is longitudinal, and there is no floscelle; so that both are sufficiently anomalous members of the genus. Some remarks on the species and its allies are made further on.
Locality.—East of the Glenelg river.
Catopygus elegans, Laube, op. cit. fig. 7, and p. 190.
This species has a pentagonal peristome, a well-developed floscelle, and a kind of plastron. It is concave inferiorly, and this is rather anomalous.
Locality.—The Banks of the Murray.
Family SPATANGIDÆ.
Holaster Australiæ, sp. nov. Plate III. figs. 12 & 13.
The test is ovoid in outline when seen from above, and is slightly grooved in front, and pointed and truncated posteriorly. It is rounded at the ambitus and over the apical part; but owing to there being a keel between the actinosome and the posterior end, the greatest height is behind the apical system. The test is thick, and only marked above by one depression, for the anterior odd ambulacrum. The apical system (Pl. III. fig. 13) is long and central, the antero-lateral ambulacra being widely separate, flush with the test, long and open, and widely separated from the posterior ambulacra. The generative pores are four in number, and the posterior pair are separated from the anterior by the ocular plates of the antero-lateral ambulacra; on the other hand the ocular plates of the posterior ambulacra are posterior to those pierced by the posterior
