THE NAUTILUS. 121 
genus Cyrena. If correctly referred to Corbicula, it would have 
priority over Corbicula obliqua Whiteaves, 1885, from the Cre- 
taceous of Canada. Not having access to the literature neces- 
sary for the determination of this question, I wrote to Dr. T. 
W. Stanton about it. He referred it to Dr. W. H. Dall, who 
replied as follows: 
** Deshayes in his revision left obliqua in Cyrena. Cossmann 
puts it in Corbicula. The lateral teeth are smooth as in Cyrena 
but long as in Corbicula. It belongs to a small group of ovoid 
species which is neither typical Cyrena nor true Corbicula. Of 
the two attributions I regard Deshayes’ as the most nearly cor- 
rect, but I should include these small oval species in a distinct 
group from either. However, as the species has been referred 
at various times to Corbicula it would probably be best to regard 
the combination as preoccupying Whiteaves’ name if it was 
made before 1885, but not otherwise.”’ 
I have no citation indicating that the combination referred to 
was made before 1885. Under the circumstances I feel that 
Deshayes’ species should be left in Cyrena or placed in a dis- 
tinct genus, and Whiteaves’ name retained for the Cretaceous 
species. If anyone thinks the latter should be renamed, then 
it would be quite fitting to name it in honor of Whiteaves, a 
name that has not been used for any species of Corbicula as far 
as I can ascertain. 
Some of the fossil Mollusca described by Hall in the report of 
the Fremont Expedition, 1845, are exceedingly troublesome. 
Though all assigned by Hall to marine genera, he stated that 
he would have considered several of them fiuviatile shells ex- 
cept for the occurrence of Nucula impressa and Cerithium fremonti- 
‘‘in the same association.’’ White, in his Review of North 
American Fossil Non-marine Mollusca, says they probably be- 
long to a fresh-water fauna, and several have been definitely 
transferred to fresh-water genera, being now well known. Fol- 
lowing is the list of Hall’s species under discussion: 
Nucula impressa— Yoldia impressa. 
Mya tellinoidea=Unio tellinoides. 
Cytherea parvula. 
Cerithium fremonti. 
