PLANORBIS DEFLECTUS. 25 



the question of priority; as the German peri- 

 odical, and Dr. Gould's work, were published the 

 same year. The later species might be called 

 dilatus, with the citation of the author to whom 

 it belongs as a species. 



PLANORBIS DEFLECTUS, Say. 



PLATE 4. FIGS. 4 7. 



P. testa discoidea, ad periphaeriam obtuse carinata, 

 utrinque concav& et similiter excavata: labio in anfractum 

 ultimum extenso: anfractibus 4 compressis. 



SYNONYMS AND REFERENCES. 



PLANORBIS DEFLECTUS, SAY. Long's Expedition to St. 



Peter's river, p. 261, pi. 15, fig. 8. 

 PLANORBIS DEFLECTUS, GOULD. Invert, of Mass., 136. 

 P. VIRENS, ADAMS. Bost. Journ. N. H., v. 3, pi. 3, fig. 16. 



DESCRIPTION. 



ANIMAL "dusky above, and with a still darker 

 line to tip of tentacula." Gould. 



SHELL discoidal, thin in texture, smooth, and 

 finely striate, with the margin obtusely cari- 

 nated: sides exhibiting about one-half of the 



K 4 



