197 



with the posterior slope of the whorl ; the outer lip is conspicu- 

 ously ecurved medially. 



Dimensions. — Of a large typical example. Length, 41 ; 

 greatest width, 22 ; length of aperture, 34 ; length of last whorl, 

 35. Of a pyriform variety, the corresponding measures are — 

 32, 20, 27-5, 28-5. 



Localities. — Eocene beds at Muddy Creek and Schnapper 

 Point. 



Affinity. — This species exhibits much individual variation in 

 shape of body-whorl and length of spire, but presents in the 

 cord-like appearance of its peripheral keel a character which 

 readily distinguishes it from other Australian species. 



A figured variety so closely resembles C. deperditus of the 

 Hampshire and Paris basins, that it is only by comparison of 

 actual specimens possible to separate them. Though in this 

 individual the gradation of the spire and the peripheral rib have 

 lost much of their prominence, yet the defining threads on the 

 keel are present — a character absent in C. deperditus ; moreover, 

 the latter is further distinguished by having two spiral and dis- 

 tant threads on the posterior area of the whorls. At the same 

 time, the Australian similitude is no more than an extreme 

 variation from a type which is obviously distinct from C. deper- 

 ditus. However, it may be well to note that our Australian 

 Cones are very difficult of specific definition, so much so that it is 

 possible to bring all the species into very close relationship, 

 through extreme individual variability. 



6. Conus heterospira, ^v^c. nor. 



Shell acutely oval, biconic, with the anterior whorls of the 

 spire gradated, the posterior ones more or less flatly depressed, 

 rarely with a regular gradated spire throughout. The pullus 

 arises abruptly from the spire as a small, smooth, shining papilla 

 of one and a-half naticiform whorls. 



Spire-whorls five ; the penultimate one medially angulated, its 

 anterior slope perpendicular, the posterior slojDe slightly inclined, 

 but with a faint medial depression ; on the ante-penultimate, the 

 keel is close to the anterior suture, thence to the pullus the 

 whorls are flat with a slight backward inclination whilst the keel 

 appears as a slight rim. 



The body-whorl is elongated and tapers to the front; the 

 peripheral keel is sharp ; the posterior slope, as also that of the 

 spire whorls, is ornamented with prominent, much-arched, growth- 

 lines, crossed by a few, usually obscure, spiral threads ; the rest 

 of the body-whorl is ornamented with close-set, equidistant, in- 

 cised lines, punctatedly impressed by the faint growth-lines. 



