100 Transactions. — Zooluyy. 



Hab. Greyinouth (E. Helms). 



Gerontia pantherina, Hutton. PI. ix., fig. i., and pi. xi., fig. r. 



Jaw slightly arcuated, smooth, striated. 



Dentition, 24-1-24. Laterals 8 or 9. 



Central tooth rectangular, rather broader than long ; the reflexed por-* 

 tion tricuspid, extendiug over half the base, the median cusp reaching the 

 posterior margin ; all the cusps with moderate cutting points. Laterals 

 tricuspid, the outer side-cusps larger than the inner ; each with a point. 

 Outer laterals, or inner marginals, bicuspid, the outer cusp smaller ; inner 

 margin of the inner cusp emarginate and with a cutting point ; a large 

 acute cutting point at the end. Outer marginals longer than broad, with 

 a broad bidentate point ; the last without any point. 



Hab. Greyinouth (E. Helms). 



The shell in this species is like macrocyclis, but the teeth are very 

 different. 



MlCROPHYSA (?) PUMILA, Hlltton. PI. ix., fig. Q. 



Jaw, none seen. 



Dentition, 13-1-13. Laterals (?). 



Central tooth longer than broad; the reflexed portion tricuspid, the 

 middle cusp longer and with a sharp point. Laterals bicuspid, the two 

 cusps separated, each with a point ; the inner cusp larger. Marginals 

 apparently like the laterals, but they are too minute to be made out dis- 

 tinctly by me. 



Hab. Christchurch (J. F. Armstrong). 



Strobila leioda, Hutton. PI. ix., fig. p. 



Jaw, none seen. 



Dentition, 12-1-12. Laterals 4. 



Central tooth rectangular, as broad as long ; the reflexed portion small, 

 tricuspid ; middle cusp not reaching the posterior margin. Laterals larger, 

 longer than broad, tricuspid, the middle cusp elongated, clavate, reaching 

 the posterior margin. Marginals broader than long, the three inner with 

 three minute points, the five outer without points. 



Hab. Greymouth (E. Helms). 



Vitrina dimidiata, Pfeiffer. PI. ix. , fig. y, and pi. xi., fig. o. 



Animal, in spirit, is very much larger than the shell ; the mantle appears 

 to be sub-central, or anterior, and is broadly expanded over the shell, leaving 

 a central opening only, but not divided into lobes ; there is no locomotive 

 disc to the foot ; the tail is pointed and without any appearance of a mucous 

 gland. 



Jam slightly arched, strongly ribbed with about fifteen rounded ribs in 

 the centre ; striated towards the extremities. 



