30 
Cases 42 to 44. 
Siphonotreta, is also shown by a series of specimens 
from the grey shales of Bulla, Victoria. From the 
Macdonnell Ranges, South Australia, are some 
fine examples of Cephalopoda (Orthoceras and 
Endoceras). 
The Lower Ordovician fossils in these cases are chiefly 
Graptolites, such as the net-like Dictyonema, 
the tuning-fork Didymograptus, and the branching 
Tetragraptus, Dichograptus, Goniograptus, 
and Clonograptus. Other interesting modifications 
are the biserial Diplograptus and Glossograptus, 
and the leaf-like Phyllograptus. Molluscoids and 
Mollusca are rare (Siphonotreta and Hyolithes). 
The Crustacea are represented by the well-distributed 
Pod-shrimps (Rhinopterocaris), whose bodies were 
enclosed in a gauzy or chitinous covering, joined 
by a hinge-line along the back. 
Fig. 33. Rhinopterocaris maccoyi Eth. fil. 
Lower Ordovician. (Castlemaine series.) 
Lerderderg River, Victoria. 
G. S. V. Coll. 
