192 RALPH TATE. 
Genus Seutellina. 
The genus is restricted to the Eocene: S. patella, Tate, Trans. 
Roy. Soc., 8. Aust., 1891, p. 279, uniquely represents it in the 
Australian beds. 
Genus Monostychia. 
Laube’s genus should be restored ; whilst Arachnoides can be 
still retained, as a representative of this more modern genus has 
occurred in the Miocene of the Gippsland Lakes, which I describe 
as follows— 
Genus Arachnoides. 
ARACHNOIDES INCISA, spec. nov., Pl. xiii. flg. 3. 
Test very flat, rising slightly towards the apical disk, the long- 
itudinal and transverse diameters are approximately equal; the 
apical disk is slightly in front of the centre. The ambitus is 
sharp and incised at the end of each interambulacral groove 
between which it is wndulose. The ambulacraare slightly sunken 
and abruptly declivous at the sides, they occupy about an equal 
space with the interambulacra. The poriferous zones reach about 
two-thirds way to the ambitus. The ornamentation in the inter- 
ambulacra is obliquely banded and minutely granular ; the granu- 
lations are without order in the ambulacral areas. The periproct 
is supramarginal, with a concave depression between it and the 
ambitus, which is here slightly incurved. The actinal area is flat. 
Antero-posterior diameter 544, transverse diameter 56°5, height 
6°5 millimetres. 
Localities:—Miocene: Red Bluff and beyond Meringa, Gipps- 
land Lakes, (three examples). 
The incised ambitus, which most markedly separates this fossil 
from the two known living species, recalls Monostychia from all 
species of which it is separable by the superior position of the 
periproct. | 
Except A. zealandie, Gray, which dates back to the Newer 
Tertiary of New Zealand, this is the first occurrence of an extinct 
