ORTMANN : TERTIARY INVERTEBRATES. 
189 
Affinities : This species, as well as the closely allied N. moerickei v. 
Ih. (=TV obtecta Moer.) from the Navidad beds, is characterized by the 
umbilical callus, which is divided by a groove. Moericke has pointed out 
that the most closely allied European form is the Oligocene N. hantoni- 
ensis Sow. (see v. Koenen, 1867, p. 148, pi. 12, f. 9), and that other 
related species are found in Cretaceous and Miocene beds of California. 
The Californian Miocene species (TV. callosa Gabb, 1869, p. 10, pi. 2, f. 17) 
more resembles Moericke’ s form, while the European N. hantoniensis is 
more like the Patagonian N. secunda. Since the California Cretaceous 
species, N. secta and globosa, are a little more different in external form, 
the closest relation of our species is with one of Oligocene age (TV. han- 
toniensis'). 
120. Natica darwini Hutton, 
pi. XXXIII, Fig. 4. 
1846 TV. solida Sowerby, in: Darwin, Geol. Observ. S. Amer., p. 255, pi. 
3, f. 40, 41 (non TV. solida Blainville). 
1864 TV. sol. Zittel, in: Novara Exp. Geol., p. 42, pi. 15, f. 6. 
1873 TV. sol. Hutton, Cat. Tert. Moll. Echin. N. Zealand, p. 9. 
1885 TV. sol. Hutton, in: Quart. Journ. Geol. Soc., v. 41, p. 550. 
1886 TV. darwini Hutton, in: Tr. N. Zealand Instit., v. 18, p. 334. 
1887 TV. sol. Philippi, Tert. & Quart. Verst. Chiles., p. 91, pi. 10, f. 10 
(nec. fig. 18). 
1889 TV. sol. Rochebrune & Mabille, in : Miss. Sci. Cap Horn, v. 6, p. 29. 
1896 TV. sol. Moericke, in: N. Jahrb. Miner, etc., Beil. Bd. 10, p. 558. 
1897 N. sol. v. Ihering, in: Rev. Mus. Paul., v. 2, p. 280. 
1899 TV. darwini v. Ihering, in: N. Jahrb. Miner., etc., v. 2, p. 29. 
1900 TV darw. Ortmann, in: Amer. Journ. Sci., v. 10, p. 380. 
Shell subglobular, thick, smooth. Spire short, suture inconspicuous. 
Umbilicus large, open, not covered by the callus ; labial callus thick in 
the upper part, truncated at the umbilicus. Mouth ovate, large. 
Measurements : Height, 35 mm, diameter, 34 mm (but it grows larger). 
Remarks: I cannot find any difference between the Patagonian fossil 
and Zittel’s figure of the New Zealandian form, except that in the latter 
the callus is not truncated at the umbilicus. 
In weathering, in this species as well as in TV. secunda , a comparatively 
larger amount of shell substance is removed at the suture, so that the 
latter appears to be situated in a groove or channel. 
