EXPLANATION OP PLATE XVL 



Oyrodoma etheridgei, Creswell. 

 Fig. 1. Imperfect specimen, showing a distinct and flattened band. 



Mourlonia duni, Eth. fil. 

 „ 2. A small example with acute spire. 



Helicotoma johnstoni. Eth. fil. 



,, 3. Another examjDle viewed from the upper side, exhibiting the 

 spire. 



,, 4. The under or umbilical side of the same, showing asutral depres- 

 sion and telescopic umbilicus. 



Trochonema etheridgei, Johnstvin. 



., 5. Shell seen from the front, showing mouth and keels. 

 „ 6. The same, seen from the back. 



Holopea wellingtonensis, Eth. fil. 



,. 7. A full-grown example, seen from the front. 



,, 8. The same, seen from the back. 



,, 9. A smaller specimen, seen from the back. 



All the specimens are in the Australian Museum, except PI. xvi.. Fig. 2, 

 which is from the Collection of the Geological Survey of N.S. Wales. 



