190 
PATAGONIAN EXPEDITIONS I PALAEONTOLOGY. 
Record of specimens : Mouth of Santa Cruz River, 4 sp.; 30 miles north 
of upper Rio Chalia, 1 good specimen, 3 doubtful casts. 
Distribution: Santa Cruz (doubtful casts, according to Sowerby) (Roch. 
& Mab.); La Cueva and Jegua quemada, Suprapatagonian, but not Pata- 
gonian beds (v. Ih. ) ; Navidad beds of Chili; Navidad (Sow., Phil., Moer.), 
Lebu (Phil.). 
New Zealand (Zitt. ), Pareora beds (Miocene, Hutt.); Chatham Isl. 
(Hutt.). 
Affinities: This species comes near those which have been called by 
the collective name of Natica her os, and are found from Miocene to Re- 
cent times on the Atlantic coast of North America, and which are divided 
by Dali (1892, pp. 372, 373) into three species. One of them, N interna 
Say, resembles our Patagonian fossil in the thick callus, but the callus is 
not suddenly truncated at the umbilicus, the umbilicus is narrower, and 
has a spiral rib inside, and further, the suture is more distinct. (I have 
compared 4 specimens from the Miocene of St. Mary’s River, Maryland, 
one of which seems to be a true N \ keros , the others belonging to N. 
interna). In N. perspectiva the suture is more like that of our species, 
but it has a sharp umbilical rib, while in the true N. heros this rib is want- 
ing, but the callus is less developed, and the suture deeper. Thus it is 
hard to say, to which of these forms N. darwini shows the closest affin- 
ity, but at any rate, it is closely allied to this Neogene group of species. 
1 2 1. Natica subtenuis v. Ihering. 
PI. XXXIII, Fig. 5. 
1897 N s. v. Ihering, in: Rev. Mils. Paul., v. 2, p. 284, textfig. 13. 
Shell ovato-subglobose, comparatively thin, smooth. Spire short, 
suture inconspicuous. Umbilicus small. Inner lip with thin callus. No 
callus on the columellar lip. Mouth large. 
Height, 40 mm ; diameter, 35 mm, another individual : height, 29 mm, 
diameter, 24 mm. 
Remarks: This species is closely allied to the foregoing, but the shell 
is thinner, the callus is less developed, the umbilicus narrower, the suture 
a little more depressed, and the external form a little higher. 
Record of specimens : Mouth of Santa Cruz River, 2 sp. 
Distribution: Jegua quemada, Suprapatagonian beds (v. Ih.). 
