SILURIAN BIVALVED MOLLUSCA OF VICTORIA. 
and along the cardinal area, boldly arched in the middle, and 
thence sloping gently to the back and basal margin. <A few 
faint irregular concentric striz or growth-lines present. 
Indications of the anterior buttress just below the umbo; this 
feature is shown more clearly in another specimen collected from 
the same locality by Mr. F. P. Spry. 
Measurements.—Height, 7.5 mm.; length, 14 mm.; depth of 
valve, about 3 mm. 
Affinities —The nearest form to the above appears to be 
Nuculites oblongatus, Conrad,* a fossil of the Hamilton Group 
of N. America, and already compared with our N. maccoyianus. 
The above species differs, however, from the N. American 
example in being slightly more convex at the umbones, more 
strongly curved on the ventral margin, and more attenuated 
posteriorly. It differs from the previously-described N. mac- 
coyianus in the more forward position of the beaks and the 
acuter posterior extremity. 
Horizon and Locality——Silurian (/ Yeringian), Wan- 
dong,t Victoria. Presented by Mr. J. T. Jutson. Also from 
the same locality, presented by Mr. F. P. Spry. [7893 (type), 
7894. | 
Family Nuculidee. 
Genus Nucuta, Lamarck, 1799. 
Nucula melbournensis, sp. nov. Pl. IL., Figs. 29, 30, 31, 31a, 
(2)82, (1)382a, (1)33, (4)33a. 
Description.—Shell broadly ovate, ventral margins evenly 
convex; cardinal line oblique, arcuate; anterior end _ short, 
obliquely rounded towards the base; posterior end broad and 
rounded. Beaks prominent, pointing slightly forward, and 
closely adpressed. Greatest thickness of valves just below the 
beaks. Surface sculptured by varices or undule at more or less 
equal intervals. Adductor impressions well-marked on the 
surface of casts. 
Measurements—Type  specimen—Length, 13.5 mm.; 
height, 10.5 mm.; width of shell near umbones, 6 mm. 
> 
*j. Hall, Pal. N. York, Vol. V., Pt. L., 1885, Lamell. II., p. 324, Pl. XLVIL., Figs. 
I-12. a 
+ The rock containing the above fossils is a dark brown irregularly bedded sandstone, 
probably younger than the dark impure limestone with Da/manites found to the westward 
of the same locality. 
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