ORTMANN I TERTIARY INVERTEBRATES. 
225 
ocene, Pliocene and Recent of the southern states of North America, the 
other from the Miocene of Florida, but M. gracilior is very much larger, 
more than double their size, and the nodules of the upper whorls are not 
present in the North American species. 
154. Marginella plicifera v. Ihering. 
PI. XXXV, Fig. 2. 
1897 M. p. v. Ihering, in: Rev. Mus. Paul., v. 2, p. 308, textfig. 19. 
Shell ovato-elongate, solid. Spire more elongated than in any other Pata- 
gonian species, conical. Whorls with rib-like, longitudinal folds, above, near 
the suture, slightly concave and with spiral striae. Columella with 4 folds. 
Height, 22 mm, diameter, 11 mm, length of mouth, 15 mm; v. Ihering 
gives: height, 31 mm, diameter, 16 mm, mouth, 20 mm. 
Remarks: v. Ihering, in the diagnosis, calls the spire “breviuscula,” 
but says farther on that it is more elongated in this species. His speci- 
mens were badly preserved and partly damaged. In our complete indi- 
vidual the spire is almost intact, and accordingly, the form appears more 
slender than in v. Ihering’ s figure. 
v. Ihering further says, in his diagnosis and description, that an im- 
pressed line accompanies the suture. Nothing of this kind is seen in his 
figure. In our specimens there is a slight depression of the upper part 
of the whorls near the suture, and in one of them there are distinct 
revolving striae (5-6) on this part of the shell. 
Record of specimens : Mouth of Santa Cruz River, 6 sp. (most of them 
greatly damaged). 
Distribution: Jegua quemada, Suprapatagonian beds (v. Ih.). 
Affinities: The sculpture of this species is very remarkable, and I can- 
not find any other species that might be compared with it in this respect. 
155. Marginella olivella nom. nov. 
PI. XXXV, Fig. 3 «’ 6 . 
1900 M. oliviformis Ortmann, in: Amer. Journ. Sci., v. 10, p. 376 (non 
M. oliviformis Tuomey & Holmes, 1857). 
Shell elongate, subcylindrically-fusiform. Spire conical. Surface of 
shell smooth and shining. Suture quite indistinct. Mouth long and 
