:^54 Frederick Cltapman .- 



sides of N. geelonr/ensis are also more strongly convex, and pro- 

 portionately broader, whilst the body chamber in N . halcomhensis 

 is higher and more nearly equal to the width, which it exceeds in 

 the later stages. 



Occurrence and Horizon. — The type specimen is from Balcombe 

 Bay; collected and presented by Mr. F. A. Cudmore. This par- 

 ticular specimen must have lain for some time on the Balcombian 

 sea-bed, since there are numerous attached valves of Dimija 

 dissimilis^ Tate, adherent to the exterior of the shell. 



Other specimens, presented by Mr. Cudmore, from the same 

 locality, are in the brephic and neanic stages. Another example, 

 in the Museum collection, in the ephebic stage, was collected by 

 the Avriter from Muddy Creek (lower beds). All the examples are 

 from strata of Balcombian age. 



Xiiutihis yeelotuietisis, Foord. (Plate TV., Figs. 7-9). 



Nautilus geelongensis, Foord, 1891, Cat. Foss. Cephalopoda 

 (Brit. Mus.). part II., p. 332, woodcut fig. 69. 



Dtscri'pfion. — The following diagnosis is quoted from A. H. 

 Foord :— 



" Sp. Char. A number of detached casts of the chaml>ers which, 

 when fitted together, make up a shell of a somewhat inflated form, 

 rather compressed on the sides, and broadly rounded on the peri- 

 phery. The aperture would be considerably wider than high. The 

 septa are moderately distant, the sutures very slightly flexuous, 

 with a dorsal lobe in the young shell. . . The siphuncle is 



nearly central, perhaps a little below the centre. Not a vestige 

 of the shell remains." 



The above description, based on a cast, gives the chief points 

 about the form of this species. Judging by the figure given by 

 Foord, the type specimen would possess about 15 chambers on the 

 last whorl, and this number coincides with the examples I have 

 identified as N. geelongensis in the Museum collection. It occurs 

 throughout the Miocene proper, or the Janjukian series of Vic- 

 toria, but chiefly in the form of a cast of the interior of the shell. 

 The shell is occasionally met with, but the beds in which it is 

 found are not usually favourable for the extraction of the fossil 

 in anything like completeness. Only one such shell is preserved 

 in the Museum collection. The shell is moderately thin, and the 

 outer layer conspicuously marked with growth lines. The um- 

 bilicus is apparently nearly closed; the sutures slightly flexuous. 



