222 
PATAGONIAN EXPEDITIONS : PALAEONTOLOGY. 
15 1 . Fusus archimedis Ortmann. 
PI. XXXIII, Fig. 20 0 ’ b . 
1900 F a. Ortmann, in: Amer. Journ. Sci., v. 10, p. 374. 
Shell fusiform ; spire shorter than the last whorl, scalariform. Whorls 
over 5 (upper part of spire missing), very prominently angulated, suture 
very deep. Upper part of whorls, above angulation, flat, obliquely 
descending from the suture, lower part of upper whorls (below angula- 
tion) very slightly convex, obliquely receding toward the lower suture. 
Angulation blunt, with a number (10-13) °f blunt, often indistinct tuber- 
cles. Sometimes these tubercles resemble indistinct longitudinal ribs, 
running for a short distance downward. Surface of shell with fine revolv- 
ing ribs on the lower part of the whorls and on the angulation, but these 
ribs disappear on the upper part of the whorls at a short distance from the 
angulation. Whole surface with distinct lines of growth, which have a 
squamulose appearance where they cross the revolving ribs. Last whorl 
large. Mouth triangular, continued into a long and straight canal. The 
revolving ribs of the last whorl become indistinct on the canal. 
Height, 50 mm (but defective at upper end), diameter, 25 mm ; diam- 
eter of a fragment, 31 mm. 
Remarks: Characterized by the strongly angulated whorls and deeply 
receding suture. The larger part of the upper flat portion of the whorls 
is quite smooth, except for growth-lines. Only near the angulation 3 to 4 
revolving ribs begin to appear, and these ribs continue downward over 
the angulation toward the canal, where they become indistinct. 
Record of specimens : San Julian, Darwin Station, 3 sp. 
Affinities: Only one species of this characteristic, strongly angulated 
form is known from the South American Tertiary: F oxytropis Philippi 
(1887, p. 50, pi. 3, f. 15) from Navidad and Tubul, but this one is much 
smaller, and the angulation much sharper, cariniform. 
I know only one other species that may be compared with ours : F. 
hector Whitfield (1892, p. 199, pi. 25, f. 3-6) from the Eocene Marls of 
New Jersey. But the latter is distinguished at once by the spiral sculp- 
ture : the upper part of the whorls, above the angulation, does not possess 
any spiral lines, and those below the angulation are much more distant 
from each other and fewer in number. But, on the whole, the type of 
sculpture is very similar in both species. 
