118 THE NAUTILUS. 
with Figs. 7, 9 and 11 northern shells. An examination of the 
youngest shells that I have seen would seem to indicate that 
Jamellidens may be the ancestral form as in very young multi- 
dentata the teeth are generally fused, so much so in fact that in . 
one of two cases I had separated them as lamellidens; but care- 
ful focusing of the microscope brought out the fused teeth, and 
measurements showed the relatively larger umbilicus. 
THE NOMENCLATURE AND SYSTEMATIC POSITIONS OF SOME NORTH 
AMERICAN FOSSILS AND RECENT MOLLUSKS. II. 
BY JUNIUS HENDERSON. 
Planorbis cirrus White, 1879, from the Tertiary of Wyoming, 
was the next year cited by the same author as though it were 
spelled cirratus. Since then the latter name has been univers- 
ally, but improperly, used instead of cirrus. 
Physa bullata White, 1886 (U. S. Geol. Surv., Bull. 36), 
from the Eocene of Utah, is preoccupied by P. bullata P. and 
M., 1838, and P. bullata Gould, 1855. However, on page 12 
of his bulletin, and in the legend of plate 3, White used the 
name bullatula for the same species, the use of bullata on page 
22, where it was described, perhaps being unintentional. 
Hence White’s species should be known as Physa bullatula. 
Whether Gould’s species should be renamed depends upon 
whether it is a valid form or a synonym of some other form, 
which I am now unable to determine. 
Physa carletont Meek, 1872, from the Cretaceous of Utah, is 
incorrectly referred to as P. carltoni by Grabau and Shimer, 
1900. Such a mistake is easily made, but unfortunately there 
is a prior use of carltoni in this genus by Lea, 1869. Though 
confusing, I suppose the names are sufficienty distinct so that 
Meek’s name may stand. His species has been so frequently 
mentioned in various reports that it would be a shame to dis- 
turb the name unless required by the rules. 
Acella haldemani White (=Tortacella haldemani, in Auricu- 
lidae), from the Cretaceous of Wyoming, is preoccupied by 
Lymnaea haldemani Deshayes, 1867 (=Acella haldemam, accord- 
