EXPLANATION OF PLATE XVIII. 



Fig, l.—Girasia sukliensis, n. sp., view of right side. X 2. 



,, 2. „ „ ,, view of dorsal side, x 2. 



,,3. ,, ,, ,, mantle seen from above, v/ith visceral 



saC; shell removed. X 4-5. 



„ 4. — Austenia dawnaensis, n. sp., view of right side, x 1-5. 



,, 5. — ,, ,, ,, view of dorsal side. X 1-5. 



„ 6. — „ ,, ,, view of frontal side. X 3-25. 



,, 7. — Girasia gravelyi, n. sp., view of right side. X 2. 



,, 8. — ,, „ „ view of dorsal side. X 2. 



