THE CAINOZOIC CIDARIDAE OF AUSTRALIA. 
Localities. — Victoria — Batesford (N.M., “H.” "C.”). Flinders (N.M., “C.”). 
s , Brid S e ’ Moorabool River, near Maude, TM 1-4 (N.M.). Kawarren 
j ’ -rl* Upper Coralline beds” at No. 3 of Wilkinson, between Castle Cove 
and Eagle’s Nest Rock, Cape Otway district (N.M., “C"). Green Gully, 
Keilor (N.M.). Clifton Bank, Muddy Creek, Hamilton (2 worn spines, “H.”). 
Tasmania Table Cape, lower beds (“C.”). Cape Barren Islands, Flinders 
Group, Bass Strait (Geol. Surv. Tas. Coll., Hobart). 
In cross-section spines are practically round : unabraded specimens dis- 
tinctly granulose, but where successive coats have peeled off, slightly different 
structures are revealed. Outer coat may carry coarse granules in longitudinal 
lines and inner coat fine granules similarly arranged. Specimens further 
abraded are smooth. Internal structure revealed by thin sections is character- 
istic of the genus Phyllacanthus (cf. Mortensen, 1928, p. 502, fig. 162). In one 
spine from Batesford (“C.”) shaft is flattened near apex. 
Measurements. — Holotype (imperfect test from Batesford) ; width of 
interamb area at ambitus, 27 mm. ; height of test, about 42 mm. Plate in 
region of ambitus ; diameter, 15 mm. ; height, 10.5 mm. ; horizontal diameter 
of boss, 9 mm. Paratype (imperfect test) ; vertical series of three uppermost 
abactinal interamb plates, 33 mm. ; greatest width of interamb zone, 39 mm. ; 
horizontal diameter of largest plate, 19 mm. Spines length of longest 
spine, figured as a paratype, 59 mm. ; diameter of ring, 5 mm. ; width near 
tip, 2 mm. 
Localities. — Victoria — Batesford ; “H., ’ “C.” and “F.A.S.” ; holotype, 
interamb zone (M.) ; paratypes, abactinal portion of interamb zone (H.) and 
5 spines (C.). Waurn Ponds, Geelong (“C.”). Curlewis polyzoal limestone 
(N.M.and“C.”). Bird Rock Cliffs, Torquay (N.M.). Airey’s Inlet ("C.”). Maude, 
locality WTM on Geol. Surv. map (N.M.). Left bank of Moorabool River, 
Lethbridge (“C.”). Flinders (N.M., “G.C.,” “H„” "C.”). Green Gully, Keilor 
(N.M.). Bairnsdale (N.M., “H.” "C.," “G.C."). Nicholson River ("C.”). 
Swan Reach ("G.C.”). Swan Reach, upper and lower beds (“C.P.C.”). Toorloo 
Creek, Lake Tyers (Ashburner Coll.). Mississippi Creek, Lakes Entrance 
("C.P.C.”). Rosehill Farm, Mitchell River (“C.”). Kawarren (“H.”). 
Bowker’s Steps, Princetown (D.). Calder River limestones, Hordern Vale, 
Cape Otway district (“C.”). Aire Coast, polyzoal limestone at locality 
Wilkinson’s 3AW (W., “C.”). Beaumaris (washed into shingle; “C.”). 
Clifton Bank, Muddy Creek, Hamilton (several worn spines, record uncertain ; 
"F.C.,” “C.”). Balcombe Bay, Mornington (one spine; N.M.). South 
Australia — Port Macdonnell (paratype, interamb zone (H.) ; also spines, “H.” 
Aldinga, upper beds (“C."). First cliff north of "Brittana,” 3 miles below 
Morgan, upper beds ("C.”). Tasmania — Table Cape, upper and lower beds 
(“C.”). Cape Barren Islands, Flinders Group, Bass Strait, in polyzoal lime- 
stone (Geol. Surv. Tas. Coll., Hobart). Western Australia — Booanya, near 
Balladonia (N.M., pres. Miss A. E. Baesjou). 
Range. — Upper Oligocene to Lower Pliocene. 
Genus PRIONOCIDARIS A. Agassiz 1863. 
This Indo-Pacific genus is represented around the Australian 
coast by three living species, in the main littoral (Mortensen, 
1929). Primary spines are often very diverse (Clark, 1925). 
Pores are conjugate. Mortensen states that various species, 
ranging from the Cretaceous of Europe and the Eocene of 
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