Lrenas Lhithia ta Vuiorui. 393 



Until lecently the only Australian Older Tertiary record of 

 Linthia was tlnit of Professor R. Tate, in 1885,' when he at- 

 tached the name of Linthia antiaustralis to an echinoid from 

 the River Murray Cliffs, near Morgan. 



In his revision of our echinoids in 1891" this was still the only 

 species known. Linthia has recently been recorded' from Vic- 

 toria, when the above Murray Cliffs fossil, L. antiaustralis, Tate, 

 has been referred to as occurring at Curlewis, near Geelong. 



In order to make the present description as complete as pos- 

 sible, I have thought it as well to include a full description of 

 the generic characters as given by Professor Martin Duncan in 

 his Revision of the Echinoidea.^ 



Genus Linthia, Mecian, 1853. 



Test variable, small to large, oval or cordiform, grooved 

 anteriorly, subaciiminate or truncated posteriorly, tumid and 

 gibbose dorsally, almost flat actinally. Apical system small, 

 excentric in front ; four perforated basal plates ; the madre- 

 porite separating the posterior basal plates and also the pos- 

 terior radial plates. 



Ambulacra diverse ; the anterior in the broad groove, the 

 pores round and small, the antero-lateral long, with the petaloid 

 parts in grooves,, moderately long, divergent, pairs of pores, 

 equal or subequal, nearly closing distally ; postero-lateral ambu- 

 lacral petals also in sunken grooves, less divergent and shorter 

 than the others. Ambulacra forming the greater part of the 

 peristomial margins, and moderately broad on either side of 

 the sternum. Peristome excentric in front, semilunar, with well- 

 developed posterior labrum. An amphisternum ; the second 

 plates of both of the zones of the right posterior ambulacrum 

 united, so as to produce ancient heteronomy. Periproct at the 

 upper part of the posterior truncation. 



1 Southern Science Record, vol. i., n.s., No. 1, Jan., 188.i. 

 •2 Trans. Roy. Soe. S..A., vol. xiv., pt. ii., p. 277. 



3 F. Cli;ipuian, Victorian Fossils, pt. ix., 1908; Proc. Roy. Soc. Vic, vol. \x.. n.s., pt. 

 ii., p. 21.'., pi. xix., f. 1, 2, 3. 



4 Jour. Lin. Soc. Lorid., Zool., vol. xxiii., 1S91, p. 233. 



