THE NAUTILUS. 121 



genus Oyrena. 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 obliqna in Cyrena. Cosmiumn. 

 puts it in Corbicula. The lateral teeth are smooth as in Cyren.a 

 but long as in Corbicula. It belongs to a small group of ovoid 

 species which is neither typical Oyrena 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 fluviatile shells ex- 

 cept for the occurrence of Nucula impressaa.nd 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. 



