72 
RECORDS OF THE AUSTRALIAN MUSEUM. 
of Mr. G. B. Pritchard, who has done much to advance our know- 
ledge of Victorian Palaeontology. 
Loc. and Horizon.— Cave Hill Quarries, Lilydale, Upper Yarra 
District, Victoria. Lilydale Limestone, Upper Silurian ; pre- 
sented by Messrs. J. Hinder and E. Smith. 
Genus Gyrodoma, gen. nov .* 
Gyrodoma etheridgei, C reswell , sp . 
PI. xvi., Fig. 1. 
Eunema etheridgei , Creswell, Proc. R. Soc. Viet., 1893, v. (n.s,), 
p. 42, t. 8, f. 2, (2 figs.). 
Ohs. — Mr. Ores well's figure represents an imperfect shell, and 
those now before me are also in the same condition, but sufficient 
characters are deductible to show that it is not referable to 
Eunema , which is an imperforate genus, with angular whorls. 
In G, etheridgei , on the other hand the whorls are boldly rounded, 
certainly seven in number and possibly more ; in PL xvi., Fig. 1 
seven are visible, whilst Creswell assumed five to be the number. 
In the latter's left hand figure, as above quoted, there seems to 
me to be an umbilicus, although no mention is made of this in the 
description. In PI. xvi., Fig. 1, a distinct and rather fiat or 
depressed band is visible, bounded by two lyrse that are certainly 
more prominent than the remainder encircling the whorls. Mr. 
C reswell's figures both distinctly portray two bands side by side, 
but the example now figured lias but one. If a double band does 
exist on some specimens, it indicates a departure towards the 
Cretaceous genus Disopeta , Gardner. The whorls decrease in size 
rapidly, the inner lip is almost straight, and with the anterior 
termination of the outer lip describes nearly a right angle. 
The presence of the regular spiral lyra* distinguishes the proposed 
new genus from the allied Goniostropha , CEhlert, Cvelocaulus , 
(Ehlert, flormotoma. , Salter, Caliendrum, , Brown, Gerithioid.es , 
(Laughton, Stegoccelia, Donald, Hypergonia , Donald, and Glyjjho- 
deta , Donald, aided in some instances by the rounded whorls of 
Gyrodoma , and the position of the band. The nonderolement of 
the whorls distinguishes the latter from Loxoplocus , Fischer, and 
the absence of all tuberculation from Murchisonia , the genus 
proper in its restricted sense. If an umbilicus exists it cannot be 
a Pithodea ) De Kon. I therefore conclude it is a new section of 
Murchisonia and call it Gyrodoma. 
Loc. and Horizon.. — Cave Hill Quarries, Lilydale, Upper Yarra 
District, Victoria. Lilydale Limestone, Upper Silurian ; pre- 
sented by Mr. J. Hinder. 
* Gyro , to turn round, and domus, a house. 
