824 'transactions. — Geology, 



Length, 1*55 inch ; height, 1-47 inch. 



Locality, Wanganui. 



Mytilicarclia tric/onopsis. 



Shell small, higher than long, strongly radiately ribbed. Eibs ten, 

 nodular, the interstices strongly concentrically striated. Anterior margin 

 straight, long ; posterior dorsal margin straight, short, then suddenly bent 

 down ; ventral margin regularly curved. 



Length, *13 inch; height, *15 inch. 



Locality. Wanganui and Petane. 



Anomia unclata. 

 Placunomia, sp. ind., Cat. Tert. Moll, of N.Z. (1873), p. 34. 



Shell broadly oval, transverse. Upper, or left, valve thin, rather in- 

 flated, the surface gently rather regularly waved ; the undulations take 

 different directions on different shells, but are more or less parallel on the 

 same individual. Muscular impressions three, confluent, forming a long 

 oval mark sloping from before the umbo to the centre of the shell ; the 

 upper one the largest, the other two sub-equal. 



Length, *83 inch ; breadth, -7 inch. 



Locality. Petane. 



EXPLANATION OF PLATE XVIII. 



1. Oliva neozelanica. 



2. Columbella varians. 



3. Turricula planata. 



4. Turricula marginata. 



5. Cominella elongata. 



6. Terebra costata. 



7. Clathurella hamiltoni. 



8. Clathurella dictyota. 



9. Clathurella nexilis. 



10. Natica laavis. 



11. Sigaretus undulatus. 



12. Sigaretus cinctus. 



13. Eulima media. 



14. Aclis costellata. 



15. Odostomia sulcata. 



16. Odostomia georgiana. 



17. Odostomia plicata. 



18. Admete ambigua. 



19. Turritella planostoma. 



20. Eissoa emarginata. 



21. Rissoa gradata. 



22. Scalaria corulum. 



