THE NAUTILUS. I 



with fragilis Rafinesque (== gracilis Barnes) the genus Pareptera 

 Ortmann, 1911, must become a synonym. 



(2) ELLIPSARIA Rafinesque, 1820. Type (by elimination) 

 fasciolaris Rafinesque (= phaseolus Barm-s) must reduce to 

 synonymy the genus Ptychobranchus Simpson, 1900, type phaseolus 

 Barnes. 



(3) AMBLEMA Rafinesque, 1820. Type (by elimination) costatus 

 Rafinesque, 1820, must take the place of Qrmodonta Schluter, 183G. 



(4) HEMISTENA Rafinesque, 1820, (a contraction of Hemilastena) 

 proposed tentatively for Lastena lata, is of course a synonym. Hence 

 the application of this generic term by Mr. C. T. Simpson, to the 

 ambigua Say (= hildreihianus Lea) can not stand. For this shell, 

 ambigna Say, I therefore propose the new generic term Simpsonaias. 



(5) EPIOBLASMA Rafinesque, 1831. Type biloba Rafinesque, 

 1831, (=foliatus Hildreth) must replace the subgentis Dysnontia 

 Agassiz, 1852. 



(6) TOXOLASMA Rafinesque, 1831. Type (by elimination) liv- 

 idus Rafinesque, 1831, (=glans Lea) must take the place of the 

 subgenus Carunculina Simpson, 1900, type texasensis Lea, and the 

 group really should have generic standing. 



(7) LEMIOX Rafinesque, 1831. Type rimosus Rafinesque, 1831 

 (== ccelatus Conrad). Since this exceedingly characteristic species 

 deserves generic rank, it must, for this species at least, take the place 

 of Micromya Agassiz. 



(8) DECURAMBIS Rafinesque, 1831. A subgenus proposed for 

 Alasmodon marginata Say, variety truncata (= scriptum Rafin- 

 esque) and atropurpureum Rafinesque, 1831 (== raveneiiana Lea). 

 This subgenus must displace Rugifera Simpson, 1900. 



(9) BARIOSTA Rafinesque, 1831. Type ponderosus Rafinesque, 

 1831, a synonym of crassidens Lamarck (= trapezoides Lea), is 

 antedated by Amblema Rafinesque, unless the U\crassedens Lamarck 

 (= trapezoides Lea) should prove to be, as Conrad suggested, of a 

 different group from the plicatus group. 



(10) SULCULARIA Rafinesque, 1831. Type (by elimination) 

 badium Rafinesque (= Marg. holstonia Lea) must be regarded as a 

 subgenus of Symphynota Lea, as constituted by Simpson, 1900, re- 

 placing in part the subgenus Pressodonta Simpson, 1900. 



(11) DIPLASMA Rafinesque, 1831. Type D. marginata Rafin- 

 esque, must take the place of Lamellidens Simpson, 1900, type 



