the floscelle; and the pores represent an absent boss which is replaced by the slit.
The ornamentation of the plastron (actinal) is very beautiful (Pl. IV. fig. 7). There is a triangular space in front of the trans- verse part of the subanal fasciole which has a slight median and central projection covered with small tubercles; and all around it the tubercles radiate, becoming large and having definite scrobicular circles and flat scrobicules until the edge of the space is reached. This ornamentation is restricted to parts of the second posterior interradial peristomial plates, and partly to the third on either side, they being crossed by the fasciole. The first plate is faintly marked with transverse ridges and distant miliaries.
The ambulacral plates on, either side of these plates are narrow; and their ornamentation is composed of distant miliaries.
Finally, the shagreen appearance of the whole test, caused by the minute granular tuberculation, is remarkable.
The localities whence Lovenia Forbesi and the varieties Woodsi and minor have been obtained are numerous. Thus the Murray cliffs have yielded the first two forms, Mount Gambier and the Hamilton Tertiaries and the Mordialloc sections No. 1, 2, 3, and 4 the same, the last yielding also the var. minor.
Genus Schizaster, Agassiz.
A large specimen, partly in the form of a cast, but with the details very well preserved, came from the "Adelaide district." It belongs to this genus; and from its resemblance to Schizaster ventricosus I am disposed to give it that specific name.
Schizaster ventricosus, Gray, Cat. of Echinida, p. 60.
Dr. Gray obtained his specimen from Australia; but the species is more common to the north and east, in Siam, the Philippines, and the Fijis.
Genus Megalaster, gen. nov.
The test is elliptical in outline, deeply incurved anteriorly and slightly truncate posteriorly. It is long, broad, but depressed; very flat inferiorly, and sloping sharply from the ambitus upwards. The apical system is in advance of the centre, and the test slopes on all sides from it; it is small in relation to the dimensions of the test, and there appear to be four small generative pores. The ambulacra are closed, petaloid, deep, and small for the size of the test. The anterior ambulacrum is aborted, and the anterior groove is broad and very deep at the ambitus. The other ambulacral petals, which are closed externally, are very deep and slightly flexuous, and the anterior pair diverge more than the posterior. The periproct is large, elliptical, transverse, and situated above the margin in a small truncation. The mouth is large, transverse, and placed
