SILURIAN BIVALVED MOLLUSCA OF VICTORIA. 
A ffinities—Both Macrodon hamiltonie, J. Hall, of the 
Hamilton Group of N. America* and Macrodus villmarensis, 
Beushausen, from the upper beds of the Middle Devonian of the 
Rhine areat bear a general resemblance to our species, but in 
many points of detail they are quite distinct, lacking the boldly 
curving ventral margin, and strong compression of the posterior 
region of the shell seen in the Australian species. 
Horizon and Locality—Silurian (Yeringian), Wandong, 
Victoria; in yellow sandstone. Type specimen collected and 
resented by Mr. F. P. Spry, after whom the species is named. 
(7950. 
Parallelodon equalis, sp. nov. Plate IV., Fig. 57. 
Description.—Shell small, elongate oval, rounded and con- 
stricted in front, broader and truncated behind, with a sharp 
umbonal ridge extending from the umbo to the postero-ventral 
margin. Beaks sub-anterior, or nearly central, inflated and 
directed forward. Cardinal line straight; ventral border 
slightly curved and approximately parallel with the hinge- 
line. Three posterior, oblique, lateral teeth visible behind the 
beaks, and close to the cardinal border. 
Measurements.—Length, 12 mm.; height, 7.5 mm.; depth 
of valve, 2.5 mm. 
Observations.—The above species belongs to a type of shell 
of which the “ Arca scitula” of McCoy} is an example. That 
species differs from ours in the more extended posterior, and in 
the strong concentric surface ornament; McCoy’s species may, 
however, eventually prove to be more nearly related to the 
North American Devonian types of this genus. 
Horizon and Locality.—Silurian (Melbournian). In brown 
mudstone, Yarra Improvement Works, 8. Yarra. Presented by 
Mr. F. P. Spry. ['7924.] 
? Parallelodon kilmoriensis, sp. nov. Pl. IV., Fig. 58, ? fig. 59. 
Description.—Shell small, rhomboid, sub-circular; length 
a little more than the height. Ventral margin boldly rounded; 
both extremities broad, the anterior short and truncate, the 
posterior margin curving upward and forward to meet the 
cardinal line. Beaks prominent, slightly anterior, pointing 
*Prelim. Notice, Lamelli., 2, p. 13, 1870. See also J. Hall, Palwont. New York, 
Vol. V., Pt. I. Lamellibranchiata, II., 1885, p. 349, Pl. LI., Figs. 1, 7, 9, 10. 
+ Abhandl. von. Preuss. Landesanst., N. F. Heft., XVII., 1895, p. 38, Pl. IV., 
Fig. 2. 
} Synopsis of the Silurian Fossils of Ireland, 1846, p. 20, Pl. IT., Fig. 6. 
[ 39 ] 
