934 THE PALEONTOLOGY OF MINNESOTA. 
[Raphistomide, 
lower lip also has become more strongly and constantly sinuate, causing a more 
oblique aperture. The evolutional modifications, it will-be noticed, are almost 
exactly opposite in the two cases. As to Omospira, it was most probably derived 
from Raphistoma, or from some unknown allied type. The relations and differences 
existing between Raphistoma, Raphistomina and Huomphalopterus are clearly shown 
by the figures in the accompanying cut: 
Fia. 5.—Sketches illustrating the character of Raphistomina, Ruphistoma and Euomphalopterus. a, 
b, c, three views of Raphistomina lapicida Salter sp.; d, e, f, similar views, x 2, of Raphistoma peracutum, a 
depressed but otherwise very typical species of the genus; g, h, i, similar views of Huomphalopterus alatus 
var. obsoletus, n. var. The last is from the Niagara group near Waldron, Indiana, and is the only American 
representative of this peculiar genus known. It differs from the European varieties of the species chiefly 
in wanting the ridge which surrounds the umbilical cavity in those forms. The umbilicus in our variety 
is also a trifle narrower than usual. 
Raphistoma, Hall, that long misunderstood and much debated genus, is now for 
the first time since 1847 correctly interpreted, limited and placed. Justice demands 
that Prof. James Hall, the author of the name, should be credited with having given 
a diagnosis that is strictly correct and sufficiently detailed to satisfy even the pres- 
ent requirements. He noticed and says distinctly that his Raphistoma has no band, 
and this fact of itself should have been accepted as fully justifying a separation 
from Pleurotomaria. Instead we find that authors have generally regarded his 
genus as indistingishable from Scalites Conrad, and both as synonyms of Pleuroto- 
maria. Salter,* it is true, gives Raphistoma, together with his Helicotoma and 
Vanuxem’s Ophileta, the rank of subgenera under Scalites (which he refers to the 
Ianthinide), and distinguished them from Pleurotomaria because of the absence of 
the spiral band. However, as we will show later on, Helicotoma and Ophileta are 
*Canadian Organic Remains, dee. 1, p. 10, 1859. 
