40 THE NAUTILUS. 



History, Mass. Institute of Technology, Academy of Natural 

 Sciences of Philadelphia. 



OBSERVATIONS ON THE GENUS SYMPHYNOTA, LEA. 



BY L. S. PRIERSON. 



In 1819 Rafinesque proposed the genus Proptera, and the 

 only described species placed in it by him was the Unio alata 

 Say, which has thus been accepted as type of the genus ever 

 since. Evidently unaquainted with Rafinesque 's writings at 

 the time, Dr. Lea, ten years afterwards (1829) proposed an 

 almost identical genus, Symphynota, and named as type, the 

 same shell, Unio alatus! (Obs. vol. 1, page 38). The genus 

 Symphynota therefore is a synonym, pure and simple, and 

 Simpson's and other's use of the name, no doubt arose from 

 overlooking the fact that Lea originally took U. alatus as type. 

 This being so, those species placed in Symphynota by Simpson 

 (Synopsis 1900, pages 662-666) must be placed in the genus 

 Lasmigona Rafinesque, 1831. Type L. costata Rafinesque 

 (1820). 



In the May (1914) NAUTILUS, page 7, I proposed the term 

 Simpsonaias for Hemflastina. This name has been preoccu- 

 pied however, and for it I propose the term Simpsoniconcha, 

 in honor of Mr. C. T. Simpson. 



VOLVIDENS, NEW GENUS. 



BY JOHN B. HENDERSON. 



I am often puzzled by the generic names applied by authors 

 to many of the small species of Antillean land-shells ; as in the 

 case of the Cuban " Thysanophora" tichostoma Pfr., a fairly 

 common species of the Matanzas and Havana Provinces. So 

 far I have never succeeded in capturing a living specimen of 

 this and therefore cannot seek the aid of an anatomist in deter- 



