SILURIAN BIVALYED MOLLUSCA OF VICTORIA 
^ Observations. — The Middle Devonian fossil identified by J. 
Phillips* as t Pullastra complanata, 'Sowerby, is distinct from 
the Silurian fossil, and is not related to Modiolopsis, since the 
posterior cardinal area is not compressed nor expanded, whilst 
the beaks are* not situated so far forward. The Victorian 
specimen agrees in almost every detail with Sowerby s species, 
which in Great Britain occurs in the Wenlock, the Upper 
Ludlow, and the Tilestone Series. 
Measurements. — The Victorian specimen has a length of 
18.5 mm.; height, 11 mm. 
Horizon and Locality. — Silurian (Melbournian). This 
striking species was found by Mr. F. P. Spry in the blue mud- 
stone of the Yarra Improvement Works, S. Yarra, and pre- 
sented by him to the National Museum. [7942.] 
Modioio'psis nasuta, Conrad sp., var. australis , nov. 
Plate VI., Fig. 78. 
References to type form — 
Cypricardites nasuta, Conrad, 1841, Ann. Rep., p. 52. 
Cypricardites nasuta, Emmons, 1842, Geol. Rep., p. 40)1, 
Fig. 4. 
Modiolopsis nasuta, Conrad sp., J. Hall, 1847, Pal. N. 
York, p. 159, PI. XXV., Fig. 7. 
Orthonotus nasutus, Conrad sp., McCoy, 1852, Brit. Pal. 
Foss., p. 275, PI. 1 I., Fig. 23. 
Orthonota, nasuta, Conrad sp., Salter, 1859, in Murchison’s 
Siluria, 3rd ed., p. 74, fossils 12, Fig. 12. Etheridge, 1888, 
Foss. Brit. Ids., Vol. I., Palaeozoic, p. 108. 
Observations. — Those elongate and modioliform shells 
which have no sharp posterior umbonal ridge, and in which the 
cardinal line is more or less curved, may be justifiably separated 
from the genus Orthonota as now understood, and placed with 
Modiolopsis (as restricted by McCoy). t The above shell is an 
example of such, which, although not so strongly arched in the 
umbonal region, yet seems to possess all the essential characters 
of Hall’s genus. 
It is interesting to note that the specific form is widely 
distributed, and there seems no reason to doubt that the Aus- 
tralian example is generally comparable with both the N. 
* Pal. Foss. Devon and Cornwall, 1841, p. 35, PI. 17, Fig. 56. 
t Brit. Pal. Foss., p. 265. 
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