Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/92

close to the notch of the anterior ambulacrum. The posterior lip is sharp and slightly projecting. The tuberculation is very small. Fascioles are not apparent.

Fig. 1.—Megalaster compressus, abactinal surface, one half the natural size.

Megalaster compressus, sp. nov. (woodcut, fig. 1).

The test is comparatively flat; and there is a marked depression behind the abactinal area and between the posterior pair of ambulacra. The antero-lateral ambulacra are slightly longer than the posterior, and in both sets the pores are very small near the apical system. The poriferous zones have the external pores elongate, and very few pores exist beyond the petals. The ocular pores are nearly as large as the generative.

Length of test 43/4 inches, breadth 41/2 inches, height 2 inches.

Locality.—Banks of the Murray.

 

IV. The Genera of Echinodermata of the Australian Tertiary and Recent Faunas.

Suborders and Families.	Tertiary Genera.			Recent Genera.
DESMOSTICHA.				$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \ \end{matrix}}\right.}$	Phyllacanthus.
Cidaridæ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		Leiocidaris.			Goniocidaris.
					Stephanocidaris.
Diadematidæ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				$\scriptstyle {\left\{{\begin{matrix}\ \\\\\ \\\ \\\ \ \end{matrix}}\right.}$	Centrostephanus.
					Echinometra.
					Strongylocentrotus.
					Sphærechinus.