SILURIAN BIVALYED MOLLUSCA OF VICTORIA. 
and Bohemia); and in the same proportion complex and adverse 
conditions probably obtained on the migratory path to North 
America. 
Further proof of the general trend of these comparative 
data as derived from other groups of the Victorian Silurian 
Mollusca is shown in the Museum collections; one notable 
example being the occurrence of a gasteropod, Ky.om/plialtix 
(lis'junctus, J. Hall,* in the Victorian Yeringian division of the 
Silurian, specimens of which are inseparable from the shells 
described by Hall, from the Lower Helderberg of New York 
(L. Devonian). The Pteropod, Coleolus aciculum, J. Halit of 
the Middle Devonian (Gencssee Slates) of North America, 
has a close relation in a form which may eventually prove to be 
identical, and which is not uncommon in the Melbournian shales 
of South Yarra4 
Comparative Table of Victorian Species of Silurian Pelecypoda, 
IDENTICAL WITH THOSE FOUND ELSEWHERE. 
Genera and Species. 
Division. 
Cardiola cornucopia:, 
Melbournian 
Goldfuss sp. (C. 
interrupt a, Sow.) 
Yeringian ... 
Prcducina ancilla, 
Barrande 
Nuculites coarctatus, 
Melbournian 
Phill. sp. 
Nucula lamellata , J. 
Hall 
Yeringian ... 
Pferinea lineata, 
Goldfuss 
? Pterinea tenuis- 
Melbournian 
triata, McCoy 
? A mbonychia acuti - 
Yeringian . . . 
cost at a, McCoy 
A ctino ptcria textu- 
J 7 
rata. Phi’ll, sp. 
A. boydi, Conrad sp. 
7 ’ 
Modiolopsis compla- 
Melbournian 
nala , Sow. sp. 
Cypricardinia con- 
Yeringian ... 
texta, Barr. 
Foreign Area. 
Europe 
Bohemia 
Great Britain 
North America 
I Great Britain ... 
( Germany 
Great Britain ... 
Wales 
England (Devon- 
shire) 
f England 
\ North America 
Great Britain 
Great Britain ... 
I Bohemia 
Formation. 
Silurian 
L. Devonian 
Sil. (Ludlow) 
Mid. and Up. De- 
vonian 
Silurian (Ludlow) 
L. Devonian 
Sil. (Wenlock to 
Up. Ludlow) 
Sil. (Wenlock and 
L. Ludlow) 
Mid. Devonian 
Sil. (Up. Ludlow) 
M. Devonian 
Sil. (Wenlock to 
passage beds) 
Sil. (Wenlock and 
L. Ludlow) 
L. Devonian 
* Pal New York, Vol. HI., 1859, p. 34°. ?1 - T A VIIL ’ Fig. 4 a,b. 
+ Pal. New York, Vol. V., Pt. IT., 1879, P- *87 ; PL XXXIIa 
+ Pfop, R. Sot. Viet,, Vol. XVI., Pt. II., N.S., 1904. p> 339? PL XXXL 3 1 ig, 7' 
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