XArilLlDJE, 
355 
types of the JS'. ziczac of Sowerby, proper to the Eocene London 
Clay, that onr Australian fossil more completely agrees ; and I can 
only doubtfully suggest the separation of it as a local variety, from 
the somewhat greater compression indicated by the slightly greater 
length of the aperture in proportion to its width ; and also a 
slightly greater curvature of the septa on the sides, as shown ,by a 
line from the apex of the lancet-shaped lobe to the inner end of the 
same septum, encroaching rather moi e on the third chamber behind. 
“ Eragments have been found indicating a diameter of about 
6 inches, but the majority of specimens found are under 2 inches.” 
This variety very closely resembles the Dax specimens of Aturia 
Atiiri \ a specimen from “Muddy Creek,” Victoria (Australia), 
being quite indistinguishable at first sight from the Dax fossils. 
On comparing, however, a specimen of the latter with the Muddy 
Creek shell, both being of equal size, it is found that the Australian 
shell has a larger siphuncular orifice than the Dax specimen, thus 
adding another point of difference to those indicated by M‘Coy as 
existing between the two forms. It may be added that the Aus- 
tralian shells from the Oligocene Tertiary beds near Mount Martha, 
from near the month of the Gellibrand River, and from the 
“ Junction Miocene ” beds of Bird Rock, south of Geelong, are pre- 
served in a manner precisely similar to that of the Bax shells, 
that is, perfectly, as if they were recent shells. 
One of the specimens figured by M‘Coy ^ is an internal cast of the 
chambers of the present variety, found in the “ hard ferruginous 
Lower Pliocene beds of Elemington.” Casts of four chambers in 
a hard ferruginous rock are contained in the British Museum, and, 
though said to be from Muddy Creek, they answer the description 
of M‘Coy’s specimen from Flemington. xV similar cast was figured 
by the Rev. J. E. Moods from Mount Gambler, under the name 
Nautilus ziczac"^. 
Horizon Miocene ? Lower Pliocene ? 
Locality. Muddy Creek, Victoria, Australia. 
Represented in the Collection by two specimens : No. C. 1548 
was presented by J. Dennant, Esq.; No. C. 1950 by Robert T. 
Litton, Esq. 
^ Prodr. of the Palaeontology of Victoria, decade iii. pi. xxiv. f. 1. 
2 Greol. Observ. in South Australia [Victoria], 1862, p. 83. 
^ There appears to be some doubt about the horizon of the beds whence the 
fossils above described were obtained. Mr. Robert Etheridge, Jun., in his 
‘Cat. Australian Foss.’ (1878) p. 171, puts them in the “Lower or Middle 
Tertiary.” 
2a 2 
