Victorian Fossils, Part XVII. 359 



Practica,lly all the specimens of .V. cliftoni in the collection had 

 lain on the sea-bed for some considerable time before being 

 covered up, for the intei'ior of the pro-ostracum generally carries 

 attached organisms, as polyzoa and Dinii/o (right or attached 

 valves). 



Occurrence and Horizon. — The type specimen was presented to 

 the Museum by Mr. F. P. Spry, and was collected by Mr. H. Lodge 

 at Clifton Bank, Muddy Creek, from the upper, broAvn polyzoal 

 marls of Balcombian age. It also occurs in the lower, blue marls 

 of the same series. There is a specimen in the Dennant coll., from 

 the same locality, and several examples in theMuseum coll., found 

 by the late Mr. W. Kershaw, at Balcombe Bay and Grice's Creek, 

 Port Phillip. These latter examples are of slightly thinner build, 

 indicative in all probability of their deeper water habitat, as 

 compai-ed with the deposits at Muddy Creek. 



EXPLANATION OF PLATES. 



Plate III. 



Fig. 1. — Aturia aturi, Basterot. Broken shell, showing the char- 

 acter and arrangement of the siphuncular funnels. Of 

 Burdigalian age. Dax. Nat. size. 



Fig. 2. — Aturia australis, McCoy. Broken shell, showing the in- 

 ternal structure. Balcombian. Grice's Creek, Port Phillip. 

 (Coll. J. F. Bailey). Nat. size. 



Fig. 3. — Nautilus halcomhensis,^s^. nov. Exterior of shell of tyi>e 

 specimen, lateral aspect; w'ith attached valves of Dimya 

 dissimilis. Balcombian. Balcombe Bay, Port Phillip. 

 (Coll. F. A. Cudmore). 7-17 nat. size. 



Fig. 4. — N. balcombe n sis, sp. nov. Opposite face of the same 

 shell, showing the internal concameration. About § nat. 

 size. 



Plate IV. 



Fig. 5. — N. balcombensis, sp. nov. Apertural aspect of the same 

 shell. Slightly less than half nat. size. 



Fig. 6. — iV. balcombensis, sp. nov. Apertural aspect of an ex- 

 ample in the neanic stage. Balcombian. Balcombe Bay, 

 Port Phillip. (Coll. F. A. Cudmore). Paratype. Nat. 

 Bize. 



