ORTMANN I TERTIARY INVERTEBRATES. 
213 
ferent. There are no species of this type in Eocene deposits of the north- 
ern hemisphere. 
143. Siphonalia noachina (Sowerby). 
PI. XXXIV, Fig. 5. 
1846 Fusns noach. Sowerby, in: Darwin, Geol. Observ. S. Amer., p. 259, 
pi. 4, f. 58, 59. 
1897 Siphonalia noach. v. Ihering, in: Rev. Mus. Paul., v. 2, p. 298. 
? 1899 S', n. Cossmann, in: Journ. Conchyliol., p. 19 (of sep. cop.), pi. n, 
fig. 2, 3 (perhaps jun.?). 
Shell ovato-fusiform, spire much shorter than the last whorl, subconical. 
Whorls 5-6, convex, last whorl very large and swollen. Surface orna- 
ments consisting of spiral grooves, which are deep and quite distant from 
each other, separated by low and rounded ribs, which are about twice as 
broad as the sulci. The bottom of the sulci is finely pitted (by lines of 
growth). Upper whorls with very indistinct longitudinal ribs (8 or 9). 
Mouth oval, large. Canal of medium length, broad, open, slightly 
curved. 
Measurements of an almost complete individual: Height, 61 mm, diam- 
eter, 35 mm ; another one, slightly damaged, measures : height, 97 mm, 
diameter, 55 mm. 
Remarks : This species grew to a considerable size : an individual, with 
the larger part of the spire broken away, measures : Height, 93 mm ; diam- 
eter, 59 mm. In large specimens the spiral sculpture of the last whorl 
becomes very strong, consisting of a number of strong, rounded, sub- 
equal ribs, separated by narrower, deep and flat grooves, the pitted appear- 
ance of which is not so strongly exhibited. 
It seems doubtful whether the small specimen described by Cossmann 
really belongs here. 
Record of specimens : Mt. of Observation, upper horizon, 2 sp. ; San 
Julian, Oven Point, 7 sp.; San Julian, Darwin Station, 1 sp.; Canon near 
Sierra Oveja, Rio Chico, 1 sp.; Lake Pueyrredon, 6oo' above base, 
1 sp. 
Distribution: San Julian (Sow.); ? Jegua quemada, Suprapatagonian 
beds (Cossm.). 
