THE CAINOZOIC CIDARIDAE OF AUSTRALIA. 
the rings meet, but on either side of each junction horizontal sutures are 
marked by a groove ; groove next median interambulacral area leads into 
deep pit between extensions of ornament already mentioned. Scrobicules not 
confluent. Median area of interambulacrum narrow. 
Specimens larger than holotype have seven coronal plates ; in more mature 
tests tubercles nearest interambulacral median area do not extend across 
suture except in actinal portion of test ; on abactinal portion surface containing 
suture becomes more prominent as a depressed, bare area linking up pits ; 
marginal surface next median suture is widened and is ornamented with more 
numerous, crowded tubercles. 
Observations. — This well-preserved little test undoubtedly 
belongs to the genus Goniocidaris. It is close to G. pentaspinosa, 
but varies from it in the ladder-like character of the inter- 
ambulacral median area. The sutural groove separating upper- 
most coronal plates from plates lying next but one to the apex 
is a feature of the living G. tubaria. The usual number of 
ambulacral plates adjacent to the largest coronal plate is seven. 
Spines have not been recognised. The interambulacral zone 
from Neumerella previously figured (1928, PI. XI, fig. 74g) as 
G. pentaspinosa is now referred to G. miirrayensis. 
Measurements. — Holotype : diameter of test, 13.25 mm. ; height, 6.25 mm. ; 
diameter across apical system, 6.5 mm. ; diameter across peristome, 5 mm. ; 
width of amb, 2 mm. ; width of interamb, 5 mm. ; width of coronal plate at 
ambitus, 3 mm. ; height, 2.5 mm. 
Localities. — Victoria — Neumerella (N.M., Reg. No. 13754). Longford 
("H.”). Flinders (“C.”). South Australia — Lower Murray Cliffs (Holotype, 
complete test, N.M.). Morgan, lower beds ("C.” ; paratype, N.M.). Wongulla, 
Murray River, lower beds (“C.”). Aldinga, lower beds (S., D., "C.”). 
Range. — Upper Oligocene to Miocene. 
Goniocidaris mortenseni sp. nov. 
Plate XIV, figs. 23, 27. 
Test rather small. Ambulacra broad, slightly sinuous. Poriferous zones 
sunken. Pores non-conjugate, oval, close together, separated by thin ridge. 
Margin of interporiferous zone on each ambulacral plate marked by a single 
large tubercle, consisting of boss and mamelon, opposite end of ridge which 
divides pairs of pores from one another ; against inner side of tubercle two 
small granules form a defined edge from which horizontal, broad, rounded 
ridges slope sharply downwards to median suture. There is therefore a pro- 
nounced nearly vertical ridge between poriferous zone and median area of 
interporiferous zone. Eight ambulacral plates adjacent to largest coronal 
plate. Number of coronal plates unknown. Scrobicules sunken ; elliptical 
in actinal region, nearly circular elsewhere ; not confluent. Perforate mamelon 
small in comparison to conical, uncrenulated boss. Scrobicular ring does not 
overhang scrobicule ; composed of large tubercles ; a few smaller tubercles lie 
beyond it, particularly in region of interambulacral median area where ornament 
ends and surface of plate drops vertically to a bare, sunken area. Suture in 
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